diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index 624b0a4..a64f07f 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -62,9 +62,9 @@ jobs:
       matrix:
         prestashop:
           # Keep the checkout ref and Docker image tag aligned when adding more supported versions.
-          - label: latest
-            image_tag: latest
-            core_ref: ''
+          - label: 9.1.0
+            image_tag: 9.1.0
+            core_ref: 9.1.0
     steps:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
@@ -74,15 +74,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v5
 
-      - name: Checkout PrestaShop core (default branch)
-        if: ${{ matrix.prestashop.core_ref == '' }}
-        uses: actions/checkout@v5
-        with:
-          repository: PrestaShop/PrestaShop
-          path: prestashop-core
-
       - name: Checkout PrestaShop core (${{ matrix.prestashop.core_ref }})
-        if: ${{ matrix.prestashop.core_ref != '' }}
         uses: actions/checkout@v5
         with:
           repository: PrestaShop/PrestaShop
@@ -106,9 +98,9 @@ jobs:
       matrix:
         prestashop:
           # Keep the checkout ref and Docker image tag aligned when adding more supported versions.
-          - label: latest
-            image_tag: latest
-            core_ref: ''
+          - label: 9.1.0
+            image_tag: 9.1.0
+            core_ref: 9.1.0
     steps:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
@@ -118,15 +110,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v5
 
-      - name: Checkout PrestaShop core (default branch)
-        if: ${{ matrix.prestashop.core_ref == '' }}
-        uses: actions/checkout@v5
-        with:
-          repository: PrestaShop/PrestaShop
-          path: prestashop-core
-
       - name: Checkout PrestaShop core (${{ matrix.prestashop.core_ref }})
-        if: ${{ matrix.prestashop.core_ref != '' }}
         uses: actions/checkout@v5
         with:
           repository: PrestaShop/PrestaShop
diff --git a/.gitignore b/.gitignore
index 692b703..11f6c75 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,9 @@
 /config_*.xml
 /translations/*.php
 /node_modules
+/tests/e2e/node_modules
+/tests/e2e/artifacts
+/tests/e2e/.env
 /vendor
 /views/node_modules
 /.php_cs.cache
diff --git a/composer.json b/composer.json
index 059b3d7..edb88cd 100644
--- a/composer.json
+++ b/composer.json
@@ -27,7 +27,8 @@
     },
     "classmap": [
       "ps_onepagecheckout.php",
-      "controllers/"
+      "controllers/",
+      "src/Checkout/Ajax/"
     ]
   },
   "scripts": {
diff --git a/controllers/admin/AdminPsOnePageCheckoutController.php b/controllers/admin/AdminPsOnePageCheckoutController.php
index b515f77..1f1ab1b 100644
--- a/controllers/admin/AdminPsOnePageCheckoutController.php
+++ b/controllers/admin/AdminPsOnePageCheckoutController.php
@@ -20,6 +20,10 @@ public function initContent()
     {
         parent::initContent();
 
+        if (!$this->viewAccess()) {
+            return;
+        }
+
         $configurationContent = $this->getBackOfficeConfigurationContent();
         if ($configurationContent !== '') {
             $this->content .= $configurationContent;
@@ -36,6 +40,11 @@ protected function getBackOfficeConfigurationContent(): string
         return $this->module->getBackOfficeConfigurationContent();
     }
 
+    public function viewAccess($disable = false)
+    {
+        return $this->hasLegacyViewAccess((bool) $disable) && $this->hasModuleConfigurePermission();
+    }
+
     public function getTwig(): ?Environment
     {
         try {
@@ -50,4 +59,14 @@ public function getTwig(): ?Environment
 
         return $legacyControllerContext->getTwig();
     }
+
+    protected function hasLegacyViewAccess(bool $disable = false): bool
+    {
+        return parent::viewAccess($disable);
+    }
+
+    protected function hasModuleConfigurePermission(): bool
+    {
+        return $this->module->getPermission('configure', $this->context->employee ?? null);
+    }
 }
diff --git a/controllers/front/AbstractOpcJsonFrontController.php b/controllers/front/AbstractOpcJsonFrontController.php
new file mode 100644
index 0000000..058a733
--- /dev/null
+++ b/controllers/front/AbstractOpcJsonFrontController.php
@@ -0,0 +1,62 @@
+<?php
+
+abstract class Ps_OnepagecheckoutAbstractOpcJsonFrontController extends ModuleFrontController
+{
+    /** @var bool */
+    public $ssl = true;
+
+    public function initContent()
+    {
+        parent::initContent();
+
+        $this->renderJsonResponse($this->handleOpcRequest());
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    abstract protected function handleOpcRequest(): array;
+
+    protected function isOpcAvailable(): bool
+    {
+        return $this->module instanceof Ps_Onepagecheckout
+            && $this->module->isOnePageCheckoutEnabled();
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    protected function buildTechnicalErrorResponse(): array
+    {
+        return $this->getTechnicalErrorResponseExtra() + [
+            'success' => false,
+            'errors' => [
+                '' => [
+                    $this->trans('One-page checkout is currently unavailable.', [], 'Shop.Notifications.Error'),
+                ],
+            ],
+        ];
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    protected function getTechnicalErrorResponseExtra(): array
+    {
+        return [];
+    }
+
+    /**
+     * @param array<string,mixed> $response
+     */
+    protected function renderJsonResponse(array $response): void
+    {
+        if (ob_get_level() > 0) {
+            ob_end_clean();
+        }
+
+        header('Content-Type: application/json');
+        $this->ajaxRender(json_encode($response));
+        exit;
+    }
+}
diff --git a/controllers/front/addresseslist.php b/controllers/front/addresseslist.php
new file mode 100644
index 0000000..18abc5e
--- /dev/null
+++ b/controllers/front/addresseslist.php
@@ -0,0 +1,66 @@
+<?php
+
+/**
+ * AJAX endpoint for module-owned OPC addresses list.
+ */
+
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerContextResolver;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutAddressesListHandler;
+
+require_once __DIR__ . '/AbstractOpcJsonFrontController.php';
+
+class Ps_OnepagecheckoutAddressesListModuleFrontController extends Ps_OnepagecheckoutAbstractOpcJsonFrontController
+{
+    /**
+     * @return array<string,mixed>
+     */
+    protected function handleOpcRequest(): array
+    {
+        if (!$this->isOpcAvailable()) {
+            return $this->buildTechnicalErrorResponse();
+        }
+
+        try {
+            $handler = new OnePageCheckoutAddressesListHandler(
+                $this->context,
+                new CheckoutCustomerContextResolver($this->context)
+            );
+            $response = $handler->handle();
+            if (empty($response['success'])) {
+                return $response;
+            }
+
+            return [
+                'success' => true,
+                'address_count' => (int) ($response['address_count'] ?? 0),
+                'delivery_html' => $this->render(
+                    'checkout/_partials/one-page-checkout/address-list',
+                    [
+                        'customer' => $response['customer'] ?? [],
+                        'prefix' => '',
+                        'selected_address' => (int) ($response['selected_delivery_address'] ?? 0),
+                    ]
+                ),
+                'billing_html' => $this->render(
+                    'checkout/_partials/one-page-checkout/address-list',
+                    [
+                        'customer' => $response['customer'] ?? [],
+                        'prefix' => 'invoice_',
+                        'selected_address' => (int) ($response['selected_invoice_address'] ?? 0),
+                    ]
+                ),
+            ];
+        } catch (Throwable $exception) {
+            PrestaShopLogger::addLog(
+                sprintf('ps_onepagecheckout addressesList runtime exception: %s', $exception->getMessage()),
+                3,
+                null,
+                'Module',
+                (int) $this->module->id,
+                true
+            );
+
+            return $this->buildTechnicalErrorResponse();
+        }
+    }
+}
diff --git a/controllers/front/AddressForm.php b/controllers/front/addressform.php
similarity index 54%
rename from controllers/front/AddressForm.php
rename to controllers/front/addressform.php
index 950bb09..aae215d 100644
--- a/controllers/front/AddressForm.php
+++ b/controllers/front/addressform.php
@@ -4,28 +4,20 @@
  * AJAX endpoint for module-owned OPC address form refresh.
  */
 
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerContextResolver;
 use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutAddressFormHandler;
 use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutFormFactory;
 
-class Ps_OnepagecheckoutAddressFormModuleFrontController extends ModuleFrontController
-{
-    /** @var bool */
-    public $ssl = true;
-
-    public function initContent()
-    {
-        parent::initContent();
-
-        $response = $this->handleAddressFormRefresh();
-        $this->renderJsonResponse($response);
-    }
+require_once __DIR__ . '/AbstractOpcJsonFrontController.php';
 
+class Ps_OnepagecheckoutAddressFormModuleFrontController extends Ps_OnepagecheckoutAbstractOpcJsonFrontController
+{
     /**
      * @return array<string,mixed>
      */
-    protected function handleAddressFormRefresh(): array
+    protected function handleOpcRequest(): array
     {
-        if (!$this->module instanceof Ps_Onepagecheckout || !$this->module->isOnePageCheckoutEnabled()) {
+        if (!$this->isOpcAvailable()) {
             return $this->buildTechnicalErrorResponse();
         }
 
@@ -35,8 +27,8 @@ protected function handleAddressFormRefresh(): array
             $templateVariables = $handler->getTemplateVariables(Tools::getAllValues());
 
             return [
-                'address_form' => $this->render(
-                    'checkout/_partials/one-page-checkout-form',
+                'addresses_section' => $this->render(
+                    'checkout/_partials/one-page-checkout/addresses-section',
                     $templateVariables
                 ),
             ];
@@ -63,34 +55,10 @@ protected function getOpcFormFactory(): OnePageCheckoutFormFactory
 
     protected function createAddressFormHandler(OnePageCheckoutFormFactory $opcFormFactory): OnePageCheckoutAddressFormHandler
     {
-        return new OnePageCheckoutAddressFormHandler($opcFormFactory->create());
-    }
-
-    /**
-     * @return array<string,mixed>
-     */
-    protected function buildTechnicalErrorResponse(): array
-    {
-        return [
-            'success' => false,
-            'errors' => [
-                '' => [
-                    $this->trans('One-page checkout is currently unavailable.', [], 'Shop.Notifications.Error'),
-                ],
-            ],
-        ];
-    }
-
-    /**
-     * @param array<string,mixed> $response
-     */
-    protected function renderJsonResponse(array $response): void
-    {
-        if (ob_get_level() > 0) {
-            ob_end_clean();
-        }
-
-        header('Content-Type: application/json');
-        $this->ajaxRender(json_encode($response));
+        return new OnePageCheckoutAddressFormHandler(
+            $opcFormFactory->create(),
+            $this->context,
+            new CheckoutCustomerContextResolver($this->context)
+        );
     }
 }
diff --git a/controllers/front/carriers.php b/controllers/front/carriers.php
new file mode 100644
index 0000000..c5123fa
--- /dev/null
+++ b/controllers/front/carriers.php
@@ -0,0 +1,47 @@
+<?php
+
+/**
+ * AJAX endpoint for module-owned OPC carriers list.
+ */
+
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutCarriersHandler;
+
+require_once __DIR__ . '/AbstractOpcJsonFrontController.php';
+
+class Ps_OnepagecheckoutCarriersModuleFrontController extends Ps_OnepagecheckoutAbstractOpcJsonFrontController
+{
+    /**
+     * @return array<string,mixed>
+     */
+    protected function handleOpcRequest(): array
+    {
+        if (!$this->isOpcAvailable()) {
+            return $this->buildTechnicalErrorResponse();
+        }
+
+        $handler = new OnePageCheckoutCarriersHandler($this->context, $this->module->getTranslator());
+        $response = $handler->handle(Tools::getAllValues());
+
+        if (!empty($response['success'])) {
+            $response['carriers_html'] = $this->render(
+                'checkout/_partials/one-page-checkout/carriers',
+                [
+                    'delivery_options' => $response['delivery_options'] ?? [],
+                    'delivery_option' => $response['delivery_option'] ?? '',
+                ]
+            );
+            if (isset($response['cart_preview'])) {
+                $response['preview'] = $this->render(
+                    'checkout/_partials/cart-summary',
+                    [
+                        'cart' => $response['cart_preview'],
+                        'static_token' => Tools::getToken(false),
+                    ]
+                );
+                unset($response['cart_preview']);
+            }
+        }
+
+        return $response;
+    }
+}
diff --git a/controllers/front/carttotals.php b/controllers/front/carttotals.php
new file mode 100644
index 0000000..b763f04
--- /dev/null
+++ b/controllers/front/carttotals.php
@@ -0,0 +1,30 @@
+<?php
+
+/**
+ * AJAX endpoint returning current cart totals for the OPC pay button.
+ */
+
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CartPresenterHelper;
+
+require_once __DIR__ . '/AbstractOpcJsonFrontController.php';
+
+class Ps_OnepagecheckoutCartTotalsModuleFrontController extends Ps_OnepagecheckoutAbstractOpcJsonFrontController
+{
+    /**
+     * @return array<string,mixed>
+     */
+    protected function handleOpcRequest(): array
+    {
+        if (!$this->isOpcAvailable()) {
+            return $this->buildTechnicalErrorResponse();
+        }
+
+        $cartPresenterHelper = new CartPresenterHelper($this->context);
+        $cartPreview = $cartPresenterHelper->presentCart();
+
+        return [
+            'success' => true,
+            'totals' => $cartPreview['totals'],
+        ];
+    }
+}
diff --git a/controllers/front/deleteaddress.php b/controllers/front/deleteaddress.php
new file mode 100644
index 0000000..af7b70f
--- /dev/null
+++ b/controllers/front/deleteaddress.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * AJAX endpoint for module-owned OPC address delete.
+ */
+
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerContextResolver;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutDeleteAddressHandler;
+
+require_once __DIR__ . '/AbstractOpcJsonFrontController.php';
+
+class Ps_OnepagecheckoutDeleteAddressModuleFrontController extends Ps_OnepagecheckoutAbstractOpcJsonFrontController
+{
+    /**
+     * @return array<string,mixed>
+     */
+    protected function handleOpcRequest(): array
+    {
+        if (!$this->isOpcAvailable()) {
+            return $this->buildTechnicalErrorResponse();
+        }
+
+        $handler = new OnePageCheckoutDeleteAddressHandler(
+            $this->context,
+            $this->module->getTranslator(),
+            new CheckoutCustomerContextResolver($this->context)
+        );
+
+        return $handler->handle(Tools::getAllValues());
+    }
+}
diff --git a/controllers/front/GuestInit.php b/controllers/front/guestinit.php
similarity index 63%
rename from controllers/front/GuestInit.php
rename to controllers/front/guestinit.php
index 00035f7..7101770 100644
--- a/controllers/front/GuestInit.php
+++ b/controllers/front/guestinit.php
@@ -7,25 +7,16 @@
 use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutGuestInitHandler;
 use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutFormFactory;
 
-class Ps_OnepagecheckoutGuestInitModuleFrontController extends ModuleFrontController
-{
-    /** @var bool */
-    public $ssl = true;
-
-    public function initContent()
-    {
-        parent::initContent();
-
-        $response = $this->handleGuestInit();
-        $this->renderJsonResponse($response);
-    }
+require_once __DIR__ . '/AbstractOpcJsonFrontController.php';
 
+class Ps_OnepagecheckoutGuestInitModuleFrontController extends Ps_OnepagecheckoutAbstractOpcJsonFrontController
+{
     /**
      * @return array<string,mixed>
      */
-    protected function handleGuestInit(): array
+    protected function handleOpcRequest(): array
     {
-        if (!$this->module instanceof Ps_Onepagecheckout || !$this->module->isOnePageCheckoutEnabled()) {
+        if (!$this->isOpcAvailable()) {
             return $this->buildTechnicalErrorResponse();
         }
 
@@ -69,32 +60,13 @@ protected function createGuestInitHandler(OnePageCheckoutFormFactory $opcFormFac
     /**
      * @return array<string,mixed>
      */
-    protected function buildTechnicalErrorResponse(): array
+    protected function getTechnicalErrorResponseExtra(): array
     {
         return [
-            'success' => false,
             'customer_created' => false,
             'id_customer' => 0,
-            'errors' => [
-                '' => [
-                    $this->trans('One-page checkout is currently unavailable.', [], 'Shop.Notifications.Error'),
-                ],
-            ],
             'token' => Tools::getToken(false),
             'static_token' => Tools::getToken(false),
         ];
     }
-
-    /**
-     * @param array<string,mixed> $response
-     */
-    protected function renderJsonResponse(array $response): void
-    {
-        if (ob_get_level() > 0) {
-            ob_end_clean();
-        }
-
-        header('Content-Type: application/json');
-        $this->ajaxRender(json_encode($response));
-    }
 }
diff --git a/controllers/front/opcsubmit.php b/controllers/front/opcsubmit.php
new file mode 100644
index 0000000..149f60e
--- /dev/null
+++ b/controllers/front/opcsubmit.php
@@ -0,0 +1,91 @@
+<?php
+
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutSessionFactory;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\Submit\OnePageCheckoutSubmitHandler;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\Submit\OnePageCheckoutSubmitProcessor;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\Submit\OnePageCheckoutSubmitValidationStateStorage;
+use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutFormFactory;
+
+require_once __DIR__ . '/AbstractOpcJsonFrontController.php';
+
+class Ps_OnepagecheckoutOpcSubmitModuleFrontController extends Ps_OnepagecheckoutAbstractOpcJsonFrontController
+{
+    /**
+     * @return array<string,mixed>
+     */
+    protected function handleOpcRequest(): array
+    {
+        if (!$this->isOpcAvailable()) {
+            return $this->buildTechnicalErrorResponse();
+        }
+
+        if (strtoupper($_SERVER['REQUEST_METHOD'] ?? '') !== 'POST') {
+            header('HTTP/1.1 405 Method Not Allowed');
+            header('Allow: POST');
+
+            return [
+                'success' => false,
+                'reload' => true,
+                'checkout_url' => $this->getCheckoutUrl(),
+            ];
+        }
+
+        try {
+            return $this->createSubmitHandler()->handle(Tools::getAllValues());
+        } catch (Throwable $exception) {
+            PrestaShopLogger::addLog(
+                sprintf('ps_onepagecheckout opcSubmit runtime exception: %s', $exception->getMessage()),
+                3,
+                null,
+                'Module',
+                (int) $this->module->id,
+                true
+            );
+
+            return $this->buildTechnicalErrorResponse();
+        }
+    }
+
+    protected function createSubmitHandler(): OnePageCheckoutSubmitHandler
+    {
+        $module = $this->module;
+        if (!$module instanceof Ps_Onepagecheckout) {
+            throw new LogicException('ps_onepagecheckout module is not available.');
+        }
+
+        $translator = $module->getTranslator();
+        $checkoutSessionFactory = new CheckoutSessionFactory($this->context, $translator);
+        $formFactory = new OnePageCheckoutFormFactory($this->context, $module);
+
+        return new OnePageCheckoutSubmitHandler(
+            $this->context,
+            $checkoutSessionFactory,
+            new OnePageCheckoutSubmitProcessor(
+                $this->context,
+                $translator,
+                $formFactory->create(),
+                new PaymentOptionsFinder(),
+                new ConditionsToApproveFinder($this->context, $translator)
+            ),
+            new OnePageCheckoutSubmitValidationStateStorage($this->context)
+        );
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    protected function getTechnicalErrorResponseExtra(): array
+    {
+        return [
+            'reload' => true,
+            'checkout_url' => $this->getCheckoutUrl(),
+        ];
+    }
+
+    private function getCheckoutUrl(): string
+    {
+        return isset($this->context->link)
+            ? (string) $this->context->link->getPageLink('order')
+            : '';
+    }
+}
diff --git a/controllers/front/paymentmethods.php b/controllers/front/paymentmethods.php
new file mode 100644
index 0000000..4cb466e
--- /dev/null
+++ b/controllers/front/paymentmethods.php
@@ -0,0 +1,53 @@
+<?php
+
+/**
+ * AJAX endpoint for module-owned OPC payment methods list.
+ */
+
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutPaymentMethodsHandler;
+
+require_once __DIR__ . '/AbstractOpcJsonFrontController.php';
+
+class Ps_OnepagecheckoutPaymentMethodsModuleFrontController extends Ps_OnepagecheckoutAbstractOpcJsonFrontController
+{
+    /**
+     * @return array<string,mixed>
+     */
+    protected function handleOpcRequest(): array
+    {
+        if (!$this->isOpcAvailable()) {
+            return $this->buildTechnicalErrorResponse();
+        }
+
+        try {
+            $handler = new OnePageCheckoutPaymentMethodsHandler($this->context);
+            $response = $handler->handle(Tools::getAllValues());
+
+            if (!empty($response['success'])) {
+                $response['payment_html'] = $this->render(
+                    'checkout/_partials/one-page-checkout/payment-methods',
+                    [
+                        'payment_options' => $response['payment_options'] ?? [],
+                        'is_free' => $response['is_free'] ?? false,
+                        'selected_payment_module' => $response['selected_payment_module'] ?? '',
+                        'selected_payment_selection_key' => $response['selected_payment_selection_key'] ?? '',
+                    ]
+                );
+                unset($response['payment_options']);
+            }
+
+            return $response;
+        } catch (Throwable $exception) {
+            PrestaShopLogger::addLog(
+                sprintf('ps_onepagecheckout paymentMethods runtime exception: %s', $exception->getMessage()),
+                3,
+                null,
+                'Module',
+                (int) $this->module->id,
+                true
+            );
+
+            return $this->buildTechnicalErrorResponse();
+        }
+    }
+}
diff --git a/controllers/front/saveaddress.php b/controllers/front/saveaddress.php
new file mode 100644
index 0000000..065269e
--- /dev/null
+++ b/controllers/front/saveaddress.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * AJAX endpoint for module-owned OPC address save.
+ */
+
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerContextResolver;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutSaveAddressHandler;
+
+require_once __DIR__ . '/AbstractOpcJsonFrontController.php';
+
+class Ps_OnepagecheckoutSaveAddressModuleFrontController extends Ps_OnepagecheckoutAbstractOpcJsonFrontController
+{
+    /**
+     * @return array<string,mixed>
+     */
+    protected function handleOpcRequest(): array
+    {
+        if (!$this->isOpcAvailable()) {
+            return $this->buildTechnicalErrorResponse();
+        }
+
+        $handler = new OnePageCheckoutSaveAddressHandler(
+            $this->context,
+            $this->module->getTranslator(),
+            new CheckoutCustomerContextResolver($this->context)
+        );
+
+        return $handler->handle(Tools::getAllValues());
+    }
+}
diff --git a/controllers/front/selectcarrier.php b/controllers/front/selectcarrier.php
new file mode 100644
index 0000000..cc46882
--- /dev/null
+++ b/controllers/front/selectcarrier.php
@@ -0,0 +1,38 @@
+<?php
+
+/**
+ * AJAX endpoint for module-owned OPC carrier selection.
+ */
+
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutSelectCarrierHandler;
+
+require_once __DIR__ . '/AbstractOpcJsonFrontController.php';
+
+class Ps_OnepagecheckoutSelectCarrierModuleFrontController extends Ps_OnepagecheckoutAbstractOpcJsonFrontController
+{
+    /**
+     * @return array<string,mixed>
+     */
+    protected function handleOpcRequest(): array
+    {
+        if (!$this->isOpcAvailable()) {
+            return $this->buildTechnicalErrorResponse();
+        }
+
+        $handler = new OnePageCheckoutSelectCarrierHandler($this->context, $this->module->getTranslator());
+        $response = $handler->handle(Tools::getAllValues());
+
+        if (!empty($response['success']) && isset($response['cart_preview'])) {
+            $response['preview'] = $this->render(
+                'checkout/_partials/cart-summary',
+                [
+                    'cart' => $response['cart_preview'],
+                    'static_token' => Tools::getToken(false),
+                ]
+            );
+            unset($response['cart_preview']);
+        }
+
+        return $response;
+    }
+}
diff --git a/controllers/front/selectpayment.php b/controllers/front/selectpayment.php
new file mode 100644
index 0000000..1b6373b
--- /dev/null
+++ b/controllers/front/selectpayment.php
@@ -0,0 +1,26 @@
+<?php
+
+/**
+ * AJAX endpoint for module-owned OPC payment selection.
+ */
+
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutSelectPaymentHandler;
+
+require_once __DIR__ . '/AbstractOpcJsonFrontController.php';
+
+class Ps_OnepagecheckoutSelectPaymentModuleFrontController extends Ps_OnepagecheckoutAbstractOpcJsonFrontController
+{
+    /**
+     * @return array<string,mixed>
+     */
+    protected function handleOpcRequest(): array
+    {
+        if (!$this->isOpcAvailable()) {
+            return $this->buildTechnicalErrorResponse();
+        }
+
+        $handler = new OnePageCheckoutSelectPaymentHandler($this->context);
+
+        return $handler->handle(Tools::getAllValues());
+    }
+}
diff --git a/controllers/front/states.php b/controllers/front/states.php
new file mode 100644
index 0000000..21ac8ce
--- /dev/null
+++ b/controllers/front/states.php
@@ -0,0 +1,26 @@
+<?php
+
+/**
+ * AJAX endpoint for module-owned OPC states list.
+ */
+
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutStatesHandler;
+
+require_once __DIR__ . '/AbstractOpcJsonFrontController.php';
+
+class Ps_OnepagecheckoutStatesModuleFrontController extends Ps_OnepagecheckoutAbstractOpcJsonFrontController
+{
+    /**
+     * @return array<string,mixed>
+     */
+    protected function handleOpcRequest(): array
+    {
+        if (!$this->isOpcAvailable()) {
+            return $this->buildTechnicalErrorResponse();
+        }
+
+        $handler = new OnePageCheckoutStatesHandler();
+
+        return $handler->handle(Tools::getAllValues());
+    }
+}
diff --git a/docs/CORE_PORTING_PLAYBOOK.md b/docs/CORE_PORTING_PLAYBOOK.md
new file mode 100644
index 0000000..deb5bb5
--- /dev/null
+++ b/docs/CORE_PORTING_PLAYBOOK.md
@@ -0,0 +1,82 @@
+# Core Porting Playbook
+
+## Goal
+
+Use this playbook when a checkout behavior exists in PrestaShop Core and must be migrated to `ps_onepagecheckout` with minimal Core changes.
+
+## Ownership rules
+
+Put a change in the module when it is:
+- checkout business logic,
+- OPC AJAX endpoint logic,
+- checkout runtime JS,
+- module BO configuration,
+- test coverage specific to the module.
+
+The module also owns runtime event emission needed by its checkout flow, including `opcFinalSubmitStarted`.
+When a Core checkout event already exists, document separately:
+- listener compatibility already expected by the existing runtime,
+- emitter ownership once the module becomes responsible for triggering the event.
+
+Put a change in Hummingbird when it is:
+- template structure,
+- section placeholders,
+- visual states,
+- style-only behavior.
+
+Put a change in Core only when:
+- the module would otherwise need an override,
+- the module cannot inject itself through an existing hook or service contract,
+- fallback native checkout behavior must stay consistent when the module is disabled.
+
+Keep Core ownership for registration and authentication entry points that are not module-specific. `RegistrationController` and its success messaging remain Core responsibilities unless a future scope explicitly changes that architecture.
+Do not introduce a module `RegistrationController` or override the Core controller as part of OPC migration work.
+Do not port legacy guest-init behaviors that reattach a fresh anonymous cart to an older guest account. When parity conflicts with the validated product rule `1 anonymous cart = 1 guest customer`, keep the module on the validated product rule and document the divergence.
+
+## Analysis procedure
+
+1. Identify the Core PR behavior and its observable contracts.
+2. Classify each change as `Core`, `module`, or `theme`.
+3. Compare the current module behavior to the Core behavior already in production.
+4. Correct parity gaps already present in the module before adding new features.
+5. Add tests before or alongside each functional lot.
+
+## Mandatory parity checklist
+
+Before porting a new Core change, verify:
+- PHP payload shape,
+- AJAX JSON keys,
+- template variables,
+- JS event names,
+- runtime URL definitions,
+- native checkout fallback when the provider module is disabled,
+- BO access control for both the dedicated module tab and the Module Manager `Configure` entry,
+- whether the behavior belongs to module runtime or must remain Core-owned.
+
+## Recommended lot order
+
+1. parity fixes,
+2. address modal,
+3. delivery dynamic,
+4. payment dynamic,
+5. documentation and runbook updates.
+
+## Test workflow
+
+Each functional lot must provide:
+- at least one unit test for the new handler/controller or runtime contract,
+- at least one integration test for the business behavior,
+- explicit coverage for any JS event contract introduced or migrated into the module,
+- rebuilt bundles when `views/js/*` changes,
+- a runbook update when FO verification points change.
+
+## Expected output for future plans
+
+Every future migration plan should state:
+- source PR or Core behavior,
+- target ownership (`Core`, `module`, `theme`),
+- blocking points,
+- files to add or update,
+- unit tests,
+- integration tests,
+- regression risks.
diff --git a/docs/DECISIONS.md b/docs/DECISIONS.md
index 2256aa9..da08d58 100644
--- a/docs/DECISIONS.md
+++ b/docs/DECISIONS.md
@@ -73,3 +73,30 @@
 - Context: `PS_ONE_PAGE_CHECKOUT_ENABLED` is no longer provisioned by Core and must be fully owned by the module lifecycle.
 - Decision: create `PS_ONE_PAGE_CHECKOUT_ENABLED` during module install with value `0`, and remove it during module uninstall instead of recreating it with value `0`.
 - Impact: module installation remains self-sufficient without activating OPC by default, and uninstall leaves no stale OPC configuration entry behind.
+
+## 2026-03-23
+
+### D-015
+- Context: `opcFinalSubmitStarted` was still treated as a Core-side runtime dependency while the checkout flow had already moved into `ps_onepagecheckout`.
+- Decision: the module owns the emission of `opcFinalSubmitStarted`, and must ship the runtime asset that emits it during final checkout submit.
+- Impact: the JS contract required by guest-init and final-submit protections stays available even when the module owns the checkout process.
+
+### D-016
+- Context: registration success messaging was discussed during OPC migration, but the module does not own the registration controller lifecycle.
+- Decision: `RegistrationController` and the `Account successfully created` success message remain Core-owned and must not be duplicated or overridden by `ps_onepagecheckout`.
+- Impact: the module stays focused on checkout behavior and avoids reintroducing registration logic outside Core.
+
+### D-017
+- Context: the dedicated BO tab `AdminPsOnePageCheckout` appends module configuration content after the legacy admin controller initialization step.
+- Decision: only append configuration content when BO view access is granted.
+- Impact: unauthorized employees cannot render the module configuration content through the dedicated BO controller.
+
+### D-018
+- Context: the migrated checkout runtime depends on an existing JS event contract that has two distinct responsibilities.
+- Decision: document and test `opcFinalSubmitStarted` as both a listener contract for existing runtime code and an emitter contract owned by `ps_onepagecheckout`.
+- Impact: the module preserves compatibility with current listeners while making ownership of the final-submit event explicit.
+
+### D-019
+- Context: guest-init legacy behavior could rebind a brand new anonymous cart to an older guest account when the submitted email already matched an existing guest.
+- Decision: ownership is `1 anonymous cart = 1 guest customer`. A guest may be reused only for the same cart already linked to that guest, never for a fresh anonymous cart.
+- Impact: a new anonymous cart must create a new guest even when the submitted email matches an older guest account; legacy reuse scenarios must not be reintroduced.
diff --git a/docs/E2E_RUNBOOK.md b/docs/E2E_RUNBOOK.md
index 35545ef..0d8539a 100644
--- a/docs/E2E_RUNBOOK.md
+++ b/docs/E2E_RUNBOOK.md
@@ -20,6 +20,59 @@ docker compose exec -T prestashop-git sh -lc 'chown -R www-data:www-data var &&
 - `DB_PASSWD=prestashop`
 - `DB_PREFIX=ps_`
 
+5. Ensure the checkout runtime loads the module-owned final submit asset:
+- `views/public/opc-submit.bundle.js`
+- browser console should expose the runtime event `opcFinalSubmitStarted` during final submit
+
+6. Before moving to a new checkout migration lot, run the module unit suite:
+```bash
+cd modules/ps_onepagecheckout
+./scripts/run-tests.sh unit
+```
+
+## Functional parity checkpoints
+
+When validating a Core-to-module port, verify at minimum:
+
+1. Guest init:
+- anonymous cart + new email,
+- anonymous cart + same email as an older guest must still create a new guest for the new cart,
+- same anonymous cart + refresh or consent toggles must not create a new guest,
+- anonymous cart + existing registered email,
+- existing guest email update,
+- invalid token,
+- missing persisted cart row.
+
+2. Address form refresh:
+- country switch refreshes the form,
+- delivery and billing form state are preserved,
+- both `updatedOpcAddressForm` and structured OPC address events are emitted.
+
+3. Address modal flow:
+- delivery modal opens in create and edit mode,
+- billing modal opens in create and edit mode,
+- changing the country reloads state options in the modal,
+- saving a delivery address refreshes the OPC form and keeps the selected address on cart,
+- saving an invoice address refreshes the OPC form and keeps `use_same_address=0` visible when applicable.
+
+4. Delivery dynamic:
+- carriers reload on initial page load,
+- carriers reload after a delivery address refresh,
+- selecting a carrier refreshes the checkout summary preview,
+- the selected carrier survives the refresh when still valid,
+- an invalid carrier selection is reset when the delivery address changes.
+
+5. Final submit parity:
+- module JS emits `opcFinalSubmitStarted` on the final OPC submit,
+- guest-init stops reacting once `opcFinalSubmitStarted` is emitted,
+- delivery option persists before final submit,
+- delivery message, recyclable, gift, and gift message persist on final submit,
+- payment methods load after the delivery state becomes valid,
+- selecting a payment method persists `selected_payment_module` across payment refreshes,
+- payment methods refresh after delivery-address and carrier updates without leaving stale panels open,
+- free carts render the payment section without blocking final submit,
+- checkout still falls back to native flow when the provider module is disabled.
+
 ## Sandbox-specific workaround
 
 In restricted environments, `maildev` import can fail with:
@@ -46,3 +99,13 @@ EOF
 2. Selector drift in FO summary blocks can create false negatives (`.cart-summary` vs legacy totals selectors).
 
 When these happen, fix the E2E selector/assertion to be locale-agnostic and structure-agnostic, not the checkout behavior.
+
+## Mandatory verification points
+
+Before declaring Core-to-module migration behavior green, verify:
+- final OPC submit emits `opcFinalSubmitStarted` exactly once per submit attempt,
+- `opc-guest-init.js` still listens to `opcFinalSubmitStarted` and stops guest-init side effects after the event,
+- guest init listeners stop reacting once final submit has started,
+- the dedicated BO tab `AdminPsOnePageCheckout` is only usable by an employee with view access,
+- the Module Manager `Configure` entry stays reachable for authorized employees and denied for unauthorized ones according to BO permissions,
+- no module controller, override, or module UI path attempts to replace `RegistrationController` or its success flash.
diff --git a/docs/RULES.md b/docs/RULES.md
index f8b1975..ecc1463 100644
--- a/docs/RULES.md
+++ b/docs/RULES.md
@@ -3,6 +3,7 @@
 ## Scope
 
 These rules are mandatory for one-page checkout implementation in the native `ps_onepagecheckout` module.
+The migration reference document is [`docs/CORE_PORTING_PLAYBOOK.md`](./CORE_PORTING_PLAYBOOK.md).
 
 ## Architecture
 
@@ -36,6 +37,19 @@ Both entry points must render the same module-owned configuration flow (no redir
 - `npm run build`
 3. When changing files under `views/js`, developers must regenerate and commit the built assets shipped by the module from `views/public` (including `*.LICENSE.txt` files). See [`README.md` → Front assets](../README.md#front-assets).
 
+## Core to module migration
+
+1. Triage every future checkout change using the playbook before coding.
+2. Correct existing parity gaps in the module before porting new Core behavior.
+3. Keep Core changes to the minimal no-override surface only.
+4. Keep checkout business logic in the module and DOM/visual ownership in Hummingbird.
+
+## Test workflow
+
+1. Each migration lot must be implemented with a story/test pair and incremental automated verification.
+2. Every lot must ship unit tests for local logic and integration tests for observable behavior.
+3. After JS changes, rebuild `views/public/*` and verify the runtime contracts through tests.
+
 ## Delivery checklist
 
 1. Unit tests updated for changed behavior.
diff --git a/ps_onepagecheckout.php b/ps_onepagecheckout.php
index 3ef3c57..3069d97 100644
--- a/ps_onepagecheckout.php
+++ b/ps_onepagecheckout.php
@@ -56,7 +56,19 @@ public function __construct()
             'Modules.Psonepagecheckout.Admin'
         );
         $this->ps_versions_compliancy = ['min' => '9.0.0', 'max' => _PS_VERSION_];
-        $this->controllers = ['GuestInit', 'AddressForm'];
+        $this->controllers = [
+            'guestinit',
+            'addressform',
+            'addresseslist',
+            'states',
+            'saveaddress',
+            'deleteaddress',
+            'carriers',
+            'selectcarrier',
+            'paymentmethods',
+            'selectpayment',
+            'opcsubmit',
+        ];
     }
 
     public function install()
@@ -129,7 +141,7 @@ public function hookActionFrontControllerSetMedia(): void
             'urls' => [
                 'guestInit' => $this->context->link->getModuleLink(
                     $this->name,
-                    'GuestInit',
+                    'guestinit',
                     ['ajax' => 1, 'action' => 'opcGuestInit'],
                     null,
                     null,
@@ -138,13 +150,103 @@ public function hookActionFrontControllerSetMedia(): void
                 ),
                 'addressForm' => $this->context->link->getModuleLink(
                     $this->name,
-                    'AddressForm',
+                    'addressform',
                     ['ajax' => 1, 'action' => 'opcAddressForm'],
                     null,
                     null,
                     null,
                     true
                 ),
+                'addressesList' => $this->context->link->getModuleLink(
+                    $this->name,
+                    'addresseslist',
+                    ['ajax' => 1, 'action' => 'opcAddressesList'],
+                    null,
+                    null,
+                    null,
+                    true
+                ),
+                'states' => $this->context->link->getModuleLink(
+                    $this->name,
+                    'states',
+                    ['ajax' => 1, 'action' => 'getStatesByCountry'],
+                    null,
+                    null,
+                    null,
+                    true
+                ),
+                'saveAddress' => $this->context->link->getModuleLink(
+                    $this->name,
+                    'saveaddress',
+                    ['ajax' => 1, 'action' => 'saveOpcAddress'],
+                    null,
+                    null,
+                    null,
+                    true
+                ),
+                'deleteAddress' => $this->context->link->getModuleLink(
+                    $this->name,
+                    'deleteaddress',
+                    ['ajax' => 1, 'action' => 'deleteOpcAddress'],
+                    null,
+                    null,
+                    null,
+                    true
+                ),
+                'carriers' => $this->context->link->getModuleLink(
+                    $this->name,
+                    'carriers',
+                    ['ajax' => 1, 'action' => 'opcCarriers'],
+                    null,
+                    null,
+                    null,
+                    true
+                ),
+                'selectCarrier' => $this->context->link->getModuleLink(
+                    $this->name,
+                    'selectcarrier',
+                    ['ajax' => 1, 'action' => 'opcSelectCarrier'],
+                    null,
+                    null,
+                    null,
+                    true
+                ),
+                'paymentMethods' => $this->context->link->getModuleLink(
+                    $this->name,
+                    'paymentmethods',
+                    ['ajax' => 1, 'action' => 'opcPaymentMethods'],
+                    null,
+                    null,
+                    null,
+                    true
+                ),
+                'selectPayment' => $this->context->link->getModuleLink(
+                    $this->name,
+                    'selectpayment',
+                    ['ajax' => 1, 'action' => 'opcSelectPayment'],
+                    null,
+                    null,
+                    null,
+                    true
+                ),
+                'opcSubmit' => $this->context->link->getModuleLink(
+                    $this->name,
+                    'opcsubmit',
+                    ['ajax' => 1, 'action' => 'opcSubmit'],
+                    null,
+                    null,
+                    null,
+                    true
+                ),
+                'cartTotals' => $this->context->link->getModuleLink(
+                    $this->name,
+                    'carttotals',
+                    ['ajax' => 1, 'action' => 'opcCartTotals'],
+                    null,
+                    null,
+                    null,
+                    true
+                ),
             ],
         ];
 
@@ -202,6 +304,32 @@ protected function registerOpcJavascriptAssets(): void
                 'priority' => 151,
             ]
         );
+
+        $this->context->controller->registerJavascript(
+            'module-ps-onepagecheckout-submit',
+            'modules/' . $this->name . '/views/public/opc-submit.bundle.js',
+            [
+                'position' => 'bottom',
+                'priority' => 149,
+            ]
+        );
+
+        foreach ([
+            ['module-ps-onepagecheckout-address-modal', 'views/public/opc-address-modal.bundle.js', 152],
+            ['module-ps-onepagecheckout-carriers', 'views/public/opc-carrier-list.bundle.js', 153],
+            ['module-ps-onepagecheckout-select-carrier', 'views/public/opc-carrier-select.bundle.js', 154],
+            ['module-ps-onepagecheckout-payment-methods', 'views/public/opc-payment-list.bundle.js', 155],
+            ['module-ps-onepagecheckout-select-payment', 'views/public/opc-payment-select.bundle.js', 156],
+        ] as [$id, $path, $priority]) {
+            $this->context->controller->registerJavascript(
+                $id,
+                'modules/' . $this->name . '/' . $path,
+                [
+                    'position' => 'bottom',
+                    'priority' => $priority,
+                ]
+            );
+        }
     }
 
     protected function addOpcJavascriptDefinition(array $javascriptDefinition): void
diff --git a/scripts/run-tests.sh b/scripts/run-tests.sh
index c25ff88..85e62b5 100755
--- a/scripts/run-tests.sh
+++ b/scripts/run-tests.sh
@@ -63,10 +63,13 @@ prepare_prestashop_volume() {
 
   docker run --rm \
     -v "${PS_ROOT_DIR_HOST}:/source:ro" \
+    -v "${REPO_DIR}:/module-source:ro" \
     -v "${PS_VOLUME}:/var/www/html" \
     alpine sh -lc '
       cp -a /source/. /var/www/html/ &&
       rm -rf /var/www/html/modules/ps_onepagecheckout &&
+      mkdir -p /var/www/html/modules/ps_onepagecheckout &&
+      cp -a /module-source/. /var/www/html/modules/ps_onepagecheckout/ &&
       chown -R 33:33 /var/www/html
     '
 }
@@ -223,7 +226,7 @@ run_phpunit() {
   fi
 
   docker run "${docker_run_args[@]}" "${PHPUNIT_IMAGE}" \
-    -lc "SYMFONY_DEPRECATIONS_HELPER=disabled /var/www/html/vendor/bin/phpunit -c ${PHPUNIT_CONFIG}"
+    -lc "if command -v composer >/dev/null 2>&1; then composer dump-autoload -o --no-interaction; fi; SYMFONY_DEPRECATIONS_HELPER=disabled /var/www/html/vendor/bin/phpunit -c ${PHPUNIT_CONFIG}"
 }
 
 case "${TEST_SUITE}" in
diff --git a/src/Checkout/Ajax/Address/OnePageCheckoutAddressFormHandler.php b/src/Checkout/Ajax/Address/OnePageCheckoutAddressFormHandler.php
new file mode 100644
index 0000000..d79edfc
--- /dev/null
+++ b/src/Checkout/Ajax/Address/OnePageCheckoutAddressFormHandler.php
@@ -0,0 +1,149 @@
+<?php
+
+/**
+ * Module AJAX handler for OPC address form refresh.
+ */
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutForm;
+
+class OnePageCheckoutAddressFormHandler
+{
+    /**
+     * @var OnePageCheckoutForm
+     */
+    private $opcForm;
+    private \Context $context;
+    private CheckoutCustomerContextResolver $customerResolver;
+
+    public function __construct(
+        OnePageCheckoutForm $opcForm,
+        ?\Context $context = null,
+        ?CheckoutCustomerContextResolver $customerResolver = null,
+    ) {
+        $this->opcForm = $opcForm;
+        $this->context = $context ?? \Context::getContext();
+        $this->customerResolver = $customerResolver ?? new CheckoutCustomerContextResolver($this->context);
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     *
+     * @return array<string,mixed>
+     */
+    public function getTemplateVariables(array $requestParameters): array
+    {
+        $deliveryAddressId = (int) ($requestParameters['id_address_delivery'] ?? 0);
+        $ownedDeliveryAddress = null;
+        $customer = $this->customerResolver->resolve();
+        $useSameAddress = array_key_exists('use_same_address', $requestParameters)
+            && (string) $requestParameters['use_same_address'] !== '0';
+
+        if ($customer instanceof \Customer) {
+            $this->opcForm->fillFromCustomer($customer);
+        }
+
+        if ($deliveryAddressId > 0) {
+            $ownedDeliveryAddress = $this->loadOwnedAddress($deliveryAddressId);
+            if ($ownedDeliveryAddress instanceof \Address) {
+                $this->opcForm->fillFromAddress($ownedDeliveryAddress);
+            }
+        }
+
+        $formParams = [];
+
+        foreach (['id_country', 'invoice_id_country', 'use_same_address', 'id_address_delivery', 'id_address_invoice'] as $name) {
+            if (!isset($requestParameters[$name])) {
+                continue;
+            }
+
+            if ($name === 'invoice_id_country' && $useSameAddress) {
+                continue;
+            }
+
+            if (in_array($name, ['id_address_delivery', 'id_address_invoice'], true) && (int) $requestParameters[$name] <= 0) {
+                continue;
+            }
+
+            if ($name === 'id_address_delivery' && !$ownedDeliveryAddress instanceof \Address) {
+                continue;
+            }
+
+            if ($name === 'id_address_invoice' && !$this->isOwnedAddressId((int) $requestParameters[$name])) {
+                continue;
+            }
+
+            $formParams[$name] = $requestParameters[$name];
+        }
+
+        if (
+            $this->shouldFallbackToDefaultDeliveryCountry($customer, $requestParameters, $deliveryAddressId)
+            && !isset($formParams['id_country'])
+        ) {
+            $formParams['id_country'] = (string) \Configuration::get('PS_COUNTRY_DEFAULT');
+        }
+
+        if (!empty($formParams)) {
+            $this->opcForm->fillWith($formParams);
+        }
+
+        return $this->buildAddressesSectionTemplateVariables();
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     */
+    private function shouldFallbackToDefaultDeliveryCountry(
+        ?\Customer $customer,
+        array $requestParameters,
+        int $deliveryAddressId,
+    ): bool {
+        if (!$customer instanceof \Customer) {
+            return false;
+        }
+
+        if ($deliveryAddressId > 0 || isset($requestParameters['id_country'])) {
+            return false;
+        }
+
+        return count($customer->getSimpleAddresses((int) $this->context->language->id)) === 0;
+    }
+
+    private function loadOwnedAddress(int $addressId): ?\Address
+    {
+        $customerId = $this->customerResolver->resolveId();
+        if ($customerId <= 0) {
+            return null;
+        }
+
+        $address = new \Address($addressId, (int) $this->context->language->id);
+        if (!\Validate::isLoadedObject($address) || (int) $address->id_customer !== $customerId) {
+            return null;
+        }
+
+        return $address;
+    }
+
+    private function isOwnedAddressId(int $addressId): bool
+    {
+        return $this->loadOwnedAddress($addressId) instanceof \Address;
+    }
+
+    /**
+     * The refreshed addresses partial needs the same top-level checkout variables
+     * as the initial step render, not just the form payload.
+     *
+     * @return array<string,mixed>
+     */
+    private function buildAddressesSectionTemplateVariables(): array
+    {
+        return $this->opcForm->getTemplateVariables() + [
+            'is_virtual_cart' => $this->context->cart->isVirtualCart(),
+            'cart' => [
+                'id_address_delivery' => (int) ($this->context->cart->id_address_delivery ?? 0),
+                'id_address_invoice' => (int) ($this->context->cart->id_address_invoice ?? 0),
+            ],
+        ];
+    }
+}
diff --git a/src/Checkout/Ajax/Address/OnePageCheckoutAddressesListHandler.php b/src/Checkout/Ajax/Address/OnePageCheckoutAddressesListHandler.php
new file mode 100644
index 0000000..1d45ea1
--- /dev/null
+++ b/src/Checkout/Ajax/Address/OnePageCheckoutAddressesListHandler.php
@@ -0,0 +1,44 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+class OnePageCheckoutAddressesListHandler
+{
+    private \Context $context;
+    private CheckoutCustomerContextResolver $customerResolver;
+    private CheckoutCustomerTemplateBuilder $customerTemplateBuilder;
+
+    public function __construct(
+        \Context $context,
+        CheckoutCustomerContextResolver $customerResolver,
+        ?CheckoutCustomerTemplateBuilder $customerTemplateBuilder = null,
+    ) {
+        $this->context = $context;
+        $this->customerResolver = $customerResolver;
+        $this->customerTemplateBuilder = $customerTemplateBuilder ?? new CheckoutCustomerTemplateBuilder(
+            $context,
+            $customerResolver
+        );
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    public function handle(): array
+    {
+        $customer = $this->customerResolver->resolve();
+        if (!$customer instanceof \Customer) {
+            return CheckoutAjaxResponse::error('Unable to resolve checkout customer.');
+        }
+
+        $customerTemplate = $this->customerTemplateBuilder->build();
+
+        return [
+            'success' => true,
+            'customer' => $customerTemplate,
+            'address_count' => count($customerTemplate['addresses'] ?? []),
+            'selected_delivery_address' => (int) ($this->context->cart->id_address_delivery ?? 0),
+            'selected_invoice_address' => (int) ($this->context->cart->id_address_invoice ?? 0),
+        ];
+    }
+}
diff --git a/src/Checkout/Ajax/Address/OnePageCheckoutDeleteAddressHandler.php b/src/Checkout/Ajax/Address/OnePageCheckoutDeleteAddressHandler.php
new file mode 100644
index 0000000..d398edf
--- /dev/null
+++ b/src/Checkout/Ajax/Address/OnePageCheckoutDeleteAddressHandler.php
@@ -0,0 +1,159 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class OnePageCheckoutDeleteAddressHandler
+{
+    private \Context $context;
+    private TranslatorInterface $translator;
+    private CheckoutCustomerContextResolver $customerResolver;
+    private CheckoutSessionFactory $checkoutSessionFactory;
+
+    public function __construct(
+        \Context $context,
+        TranslatorInterface $translator,
+        CheckoutCustomerContextResolver $customerResolver,
+        ?CheckoutSessionFactory $checkoutSessionFactory = null,
+    ) {
+        $this->context = $context;
+        $this->translator = $translator;
+        $this->customerResolver = $customerResolver;
+        $this->checkoutSessionFactory = $checkoutSessionFactory ?? new CheckoutSessionFactory($context, $translator);
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     *
+     * @return array<string,mixed>
+     */
+    public function handle(array $requestParameters = []): array
+    {
+        $customer = $this->customerResolver->resolve();
+        if (!$customer instanceof \Customer) {
+            return CheckoutAjaxResponse::error('Unable to resolve checkout customer.');
+        }
+
+        $address = $this->loadOwnedAddress($customer, (int) ($requestParameters['id_address'] ?? 0));
+        if (!$address instanceof \Address) {
+            return CheckoutAjaxResponse::error('Unable to load the requested address.');
+        }
+
+        $addressId = (int) $address->id;
+
+        $deletedActiveDeliveryAddress = \Validate::isLoadedObject($this->context->cart)
+            && (int) $this->context->cart->id_address_delivery === $addressId;
+        $deletedActiveInvoiceAddress = \Validate::isLoadedObject($this->context->cart)
+            && (int) $this->context->cart->id_address_invoice === $addressId;
+
+        if (!$this->buildAddressPersister($customer)->delete($address, \Tools::getToken(true, $this->context))) {
+            return CheckoutAjaxResponse::error('Unable to delete address.');
+        }
+
+        $remainingAddresses = $customer->getAddresses((int) $this->context->language->id);
+        $remainingAddressIds = array_map(static function (array $customerAddress): int {
+            return (int) ($customerAddress['id_address'] ?? 0);
+        }, $remainingAddresses);
+        $fallbackAddressId = !empty($remainingAddressIds) ? (int) reset($remainingAddressIds) : 0;
+
+        $this->synchronizeCartAddressesAfterDeletion(
+            $addressId,
+            $remainingAddressIds,
+            $fallbackAddressId,
+            $deletedActiveDeliveryAddress,
+            $deletedActiveInvoiceAddress
+        );
+
+        return [
+            'success' => true,
+            'id_address' => $addressId,
+            'message' => $this->translator->trans(
+                'Address successfully deleted.',
+                [],
+                'Shop.Notifications.Success'
+            ),
+        ];
+    }
+
+    private function buildAddressPersister(\Customer $customer): \CustomerAddressPersister
+    {
+        $cart = \Validate::isLoadedObject($this->context->cart) ? $this->context->cart : new \Cart();
+
+        return new \CustomerAddressPersister(
+            $customer,
+            $cart,
+            \Tools::getToken(true, $this->context)
+        );
+    }
+
+    private function loadOwnedAddress(\Customer $customer, int $addressId): ?\Address
+    {
+        if ($addressId <= 0) {
+            return null;
+        }
+
+        $address = new \Address($addressId, (int) $this->context->language->id);
+        if (!\Validate::isLoadedObject($address)) {
+            return null;
+        }
+
+        if ((int) $address->id_customer !== (int) $customer->id) {
+            return null;
+        }
+
+        return $address;
+    }
+
+    /**
+     * @param list<int> $remainingAddressIds
+     */
+    private function synchronizeCartAddressesAfterDeletion(
+        int $deletedAddressId,
+        array $remainingAddressIds,
+        int $fallbackAddressId,
+        bool $deletedActiveDeliveryAddress,
+        bool $deletedActiveInvoiceAddress,
+    ): void {
+        if (!\Validate::isLoadedObject($this->context->cart)) {
+            return;
+        }
+
+        $deliveryAddressId = $this->resolveRemainingCartAddressId(
+            (int) $this->context->cart->id_address_delivery,
+            $deletedAddressId,
+            $remainingAddressIds,
+            $fallbackAddressId
+        );
+        $invoiceAddressId = $this->resolveRemainingCartAddressId(
+            (int) $this->context->cart->id_address_invoice,
+            $deletedAddressId,
+            $remainingAddressIds,
+            $fallbackAddressId
+        );
+
+        $checkoutSession = $this->checkoutSessionFactory->create();
+        $checkoutSession->setIdAddressDelivery($deliveryAddressId);
+        $checkoutSession->setIdAddressInvoice($invoiceAddressId);
+
+        if ($deletedActiveDeliveryAddress || $deletedActiveInvoiceAddress) {
+            $this->context->cart->setDeliveryOption(null);
+        }
+    }
+
+    /**
+     * @param list<int> $remainingAddressIds
+     */
+    private function resolveRemainingCartAddressId(
+        int $currentAddressId,
+        int $deletedAddressId,
+        array $remainingAddressIds,
+        int $fallbackAddressId,
+    ): int {
+        if ($currentAddressId === $deletedAddressId || !in_array($currentAddressId, $remainingAddressIds, true)) {
+            return $fallbackAddressId;
+        }
+
+        return $currentAddressId;
+    }
+}
diff --git a/src/Checkout/Ajax/Address/OnePageCheckoutSaveAddressHandler.php b/src/Checkout/Ajax/Address/OnePageCheckoutSaveAddressHandler.php
new file mode 100644
index 0000000..bad8047
--- /dev/null
+++ b/src/Checkout/Ajax/Address/OnePageCheckoutSaveAddressHandler.php
@@ -0,0 +1,136 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutAddressForm;
+use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutAddressFormatter;
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class OnePageCheckoutSaveAddressHandler
+{
+    private \Context $context;
+    private TranslatorInterface $translator;
+    private CheckoutCustomerContextResolver $customerResolver;
+
+    public function __construct(
+        \Context $context,
+        TranslatorInterface $translator,
+        CheckoutCustomerContextResolver $customerResolver,
+    ) {
+        $this->context = $context;
+        $this->translator = $translator;
+        $this->customerResolver = $customerResolver;
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     *
+     * @return array<string,mixed>
+     */
+    public function handle(array $requestParameters = []): array
+    {
+        $customerId = $this->customerResolver->resolveId();
+        if ($customerId <= 0) {
+            return CheckoutAjaxResponse::error('Unable to resolve checkout customer.');
+        }
+
+        $addressType = (string) ($requestParameters['address_type'] ?? 'delivery');
+        $prefix = $addressType === 'invoice' ? 'invoice_' : '';
+        $addressId = (int) ($requestParameters['id_address'] ?? 0);
+        $address = $addressId > 0 ? new \Address($addressId, (int) $this->context->language->id) : new \Address();
+
+        if ($addressId > 0 && (!\Validate::isLoadedObject($address) || (int) $address->id_customer !== $customerId)) {
+            return CheckoutAjaxResponse::error('Unable to load the requested address.');
+        }
+
+        $addressForm = $this->createAddressForm();
+        $addressForm->fillFromRequest($requestParameters, $prefix);
+        if (!$addressForm->validate()) {
+            return CheckoutAjaxResponse::validation($addressForm->getErrors());
+        }
+
+        $this->hydrateAddressFromForm($address, $addressForm, $addressType, $customerId);
+
+        if (!$this->buildAddressPersister($customerId)->save($address, \Tools::getToken(true, $this->context))) {
+            return CheckoutAjaxResponse::error('Unable to save address.');
+        }
+
+        if (\Validate::isLoadedObject($this->context->cart)) {
+            if ($addressType === 'invoice') {
+                $this->context->cart->id_address_invoice = (int) $address->id;
+            } else {
+                $this->context->cart->id_address_delivery = (int) $address->id;
+
+                if ((string) ($requestParameters['use_same_address'] ?? '1') !== '0') {
+                    $this->context->cart->id_address_invoice = (int) $address->id;
+                }
+            }
+
+            $this->context->cart->update();
+        }
+
+        return [
+            'success' => true,
+        ];
+    }
+
+    private function createAddressForm(): OnePageCheckoutAddressForm
+    {
+        return new OnePageCheckoutAddressForm(
+            $this->context->smarty,
+            $this->context->language,
+            $this->translator,
+            $this->createAddressFormatter()
+        );
+    }
+
+    private function createAddressFormatter(): OnePageCheckoutAddressFormatter
+    {
+        $country = $this->context->country;
+        if (!$country instanceof \Country) {
+            $country = new \Country(
+                (int) \Configuration::get('PS_COUNTRY_DEFAULT'),
+                (int) ($this->context->language->id ?? 0)
+            );
+        }
+
+        $availableCountries = \Configuration::get('PS_RESTRICT_DELIVERED_COUNTRIES')
+            ? \Carrier::getDeliveredCountries((int) $this->context->language->id, true, true)
+            : \Country::getCountries((int) $this->context->language->id, true);
+
+        return new OnePageCheckoutAddressFormatter(
+            $country,
+            $this->translator,
+            $availableCountries
+        );
+    }
+
+    private function hydrateAddressFromForm(
+        \Address $address,
+        OnePageCheckoutAddressForm $addressForm,
+        string $addressType,
+        int $customerId,
+    ): void {
+        $address = $addressForm->buildAddress($address);
+
+        $address->id_customer = $customerId;
+        $address->alias = trim((string) ($address->alias ?: ($addressType === 'invoice'
+            ? $this->translator->trans('Invoice address', [], 'Shop.Theme.Checkout')
+            : $this->translator->trans('My Address', [], 'Shop.Theme.Checkout'))));
+        $address->id_country = (int) $address->id_country;
+        $address->id_state = (int) ($address->id_state ?: 0);
+        \Hook::exec('actionSubmitCustomerAddressForm', ['address' => &$address]);
+    }
+
+    private function buildAddressPersister(int $customerId): \CustomerAddressPersister
+    {
+        $customer = new \Customer($customerId);
+        $cart = \Validate::isLoadedObject($this->context->cart) ? $this->context->cart : new \Cart();
+
+        return new \CustomerAddressPersister(
+            $customer,
+            $cart,
+            \Tools::getToken(true, $this->context)
+        );
+    }
+}
diff --git a/src/Checkout/Ajax/Address/OnePageCheckoutStatesHandler.php b/src/Checkout/Ajax/Address/OnePageCheckoutStatesHandler.php
new file mode 100644
index 0000000..451c375
--- /dev/null
+++ b/src/Checkout/Ajax/Address/OnePageCheckoutStatesHandler.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+class OnePageCheckoutStatesHandler
+{
+    /**
+     * @param array<string,mixed> $requestParameters
+     *
+     * @return array<string,mixed>
+     */
+    public function handle(array $requestParameters = []): array
+    {
+        $countryId = (int) ($requestParameters['id_country'] ?? 0);
+        if ($countryId <= 0) {
+            return [
+                'success' => true,
+                'id_country' => 0,
+                'contains_states' => false,
+                'states' => [],
+            ];
+        }
+
+        $states = \State::getStatesByIdCountry($countryId);
+
+        return [
+            'success' => true,
+            'id_country' => $countryId,
+            'contains_states' => !empty($states),
+            'states' => $states,
+        ];
+    }
+}
diff --git a/src/Checkout/Ajax/Address/OpcTempAddress.php b/src/Checkout/Ajax/Address/OpcTempAddress.php
new file mode 100644
index 0000000..601bf48
--- /dev/null
+++ b/src/Checkout/Ajax/Address/OpcTempAddress.php
@@ -0,0 +1,90 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+class OpcTempAddress
+{
+    private \Context $context;
+    private int $tempInvoiceAddressId = 0;
+    private int $originalInvoiceAddressId = 0;
+
+    public function __construct(\Context $context)
+    {
+        $this->context = $context;
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     */
+    public function createFromRequest(array $requestParameters = []): int
+    {
+        $idCountry = (int) ($requestParameters['id_country'] ?? $requestParameters['delivery_id_country'] ?? 0);
+        if ($idCountry <= 0) {
+            return 0;
+        }
+
+        $tempAddressId = $this->insert(
+            $idCountry,
+            (int) ($requestParameters['id_state'] ?? $requestParameters['delivery_id_state'] ?? 0),
+            (string) ($requestParameters['postcode'] ?? $requestParameters['delivery_postcode'] ?? '00000'),
+            (string) ($requestParameters['city'] ?? $requestParameters['delivery_city'] ?? '-')
+        );
+
+        $this->context->cart->id_address_delivery = $tempAddressId;
+
+        if ((string) \Configuration::get('PS_TAX_ADDRESS_TYPE') === 'id_address_invoice') {
+            $invoiceIdCountry = (int) ($requestParameters['invoice_id_country'] ?? 0) ?: $idCountry;
+            $this->originalInvoiceAddressId = (int) $this->context->cart->id_address_invoice;
+            $this->tempInvoiceAddressId = $this->insert(
+                $invoiceIdCountry,
+                (int) ($requestParameters['invoice_id_state'] ?? $requestParameters['id_state'] ?? $requestParameters['delivery_id_state'] ?? 0),
+                (string) ($requestParameters['invoice_postcode'] ?? $requestParameters['postcode'] ?? $requestParameters['delivery_postcode'] ?? '00000'),
+                (string) ($requestParameters['invoice_city'] ?? $requestParameters['city'] ?? $requestParameters['delivery_city'] ?? '-')
+            );
+            $this->context->cart->id_address_invoice = $this->tempInvoiceAddressId;
+        }
+
+        $this->context->cart->save();
+
+        return $tempAddressId;
+    }
+
+    public function cleanup(int $tempAddressId, int $originalAddressId): void
+    {
+        $this->context->cart->id_address_delivery = $originalAddressId;
+
+        if ($this->tempInvoiceAddressId > 0) {
+            $this->context->cart->id_address_invoice = $this->originalInvoiceAddressId;
+        }
+
+        $this->context->cart->save();
+        \Db::getInstance()->delete('address', 'id_address = ' . (int) $tempAddressId);
+
+        if ($this->tempInvoiceAddressId > 0) {
+            \Db::getInstance()->delete('address', 'id_address = ' . (int) $this->tempInvoiceAddressId);
+            $this->tempInvoiceAddressId = 0;
+            $this->originalInvoiceAddressId = 0;
+        }
+    }
+
+    private function insert(int $idCountry, int $idState, string $postcode, string $city): int
+    {
+        \Db::getInstance()->insert('address', [
+            'id_country' => $idCountry,
+            'id_state' => $idState,
+            'id_customer' => (int) $this->context->customer->id,
+            'alias' => 'temp_opc_' . bin2hex(random_bytes(8)),
+            'firstname' => '-',
+            'lastname' => '-',
+            'address1' => '-',
+            'city' => $city ?: '-',
+            'postcode' => $postcode ?: '00000',
+            'active' => 1,
+            'deleted' => 0,
+            'date_add' => date('Y-m-d H:i:s'),
+            'date_upd' => date('Y-m-d H:i:s'),
+        ]);
+
+        return (int) \Db::getInstance()->Insert_ID();
+    }
+}
diff --git a/src/Checkout/Ajax/Carrier/OnePageCheckoutCarriersHandler.php b/src/Checkout/Ajax/Carrier/OnePageCheckoutCarriersHandler.php
new file mode 100644
index 0000000..6fe5c80
--- /dev/null
+++ b/src/Checkout/Ajax/Carrier/OnePageCheckoutCarriersHandler.php
@@ -0,0 +1,141 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class OnePageCheckoutCarriersHandler
+{
+    private \Context $context;
+    private TranslatorInterface $translator;
+    private CheckoutCustomerContextResolver $customerResolver;
+    private CheckoutSessionFactory $checkoutSessionFactory;
+    private CartPresenterHelper $cartPresenterHelper;
+    private TempAddressCarrierSelectionStorage $tempCarrierSelectionStorage;
+
+    public function __construct(
+        \Context $context,
+        TranslatorInterface $translator,
+        ?\DeliveryOptionsFinder $deliveryOptionsFinder = null,
+        ?CheckoutCustomerContextResolver $customerResolver = null,
+        ?CheckoutSessionFactory $checkoutSessionFactory = null,
+        ?CartPresenterHelper $cartPresenterHelper = null,
+        ?TempAddressCarrierSelectionStorage $tempCarrierSelectionStorage = null,
+    ) {
+        $this->context = $context;
+        $this->translator = $translator;
+        $this->customerResolver = $customerResolver ?? new CheckoutCustomerContextResolver($context);
+        $this->checkoutSessionFactory = $checkoutSessionFactory ?? new CheckoutSessionFactory($context, $translator, $deliveryOptionsFinder);
+        $this->cartPresenterHelper = $cartPresenterHelper ?? new CartPresenterHelper($context);
+        $this->tempCarrierSelectionStorage = $tempCarrierSelectionStorage ?? new TempAddressCarrierSelectionStorage($context);
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     *
+     * @return array<string,mixed>
+     */
+    public function handle(array $requestParameters = []): array
+    {
+        if (!\Validate::isLoadedObject($this->context->cart)) {
+            return CheckoutAjaxResponse::error('Unable to resolve checkout cart.');
+        }
+
+        $originalAddressId = (int) $this->context->cart->id_address_delivery;
+        $tempAddress = new OpcTempAddress($this->context);
+        $tempAddressId = 0;
+
+        try {
+            if (!empty($requestParameters['id_address_delivery'])) {
+                $requestedAddressId = (int) $requestParameters['id_address_delivery'];
+                if (!$this->isOwnedCheckoutAddress($requestedAddressId)) {
+                    return CheckoutAjaxResponse::error(
+                        $this->translator->trans('Invalid delivery address.', [], 'Shop.Notifications.Error'),
+                        'id_address_delivery'
+                    );
+                }
+
+                $this->context->cart->id_address_delivery = $requestedAddressId;
+                $this->context->cart->save();
+                $this->tempCarrierSelectionStorage->clear();
+            } else {
+                $tempAddressId = $tempAddress->createFromRequest($requestParameters);
+            }
+
+            if ((int) $this->context->cart->id_address_delivery <= 0) {
+                return [
+                    'success' => true,
+                    'delivery_options' => [],
+                    'delivery_option' => '',
+                    'selected_delivery_option' => '',
+                    'id_address_delivery' => 0,
+                ];
+            }
+
+            $persistedTempOption = '';
+            if ($tempAddressId > 0 && $originalAddressId <= 0) {
+                $persistedTempOption = $this->tempCarrierSelectionStorage->get();
+                if ($persistedTempOption !== '') {
+                    $this->checkoutSessionFactory->create()->setDeliveryOption([
+                        (int) $this->context->cart->id_address_delivery => $persistedTempOption,
+                    ]);
+                }
+            }
+
+            $finder = $this->checkoutSessionFactory->createDeliveryOptionsFinder();
+            $deliveryOptions = $finder->getDeliveryOptions();
+            $selectedDeliveryOption = $finder->getSelectedDeliveryOption();
+            $hadSelectedDeliveryOption = (bool) $selectedDeliveryOption;
+
+            if ($selectedDeliveryOption && !isset($deliveryOptions[$selectedDeliveryOption])) {
+                $selectedDeliveryOption = null;
+            }
+
+            if ($persistedTempOption !== '') {
+                if (isset($deliveryOptions[$persistedTempOption])) {
+                    $selectedDeliveryOption = $persistedTempOption;
+                } else {
+                    $this->tempCarrierSelectionStorage->clear();
+                }
+            }
+
+            $deliveryAddressId = $tempAddressId ?: (int) $this->context->cart->id_address_delivery;
+
+            if ($selectedDeliveryOption && $deliveryAddressId > 0) {
+                $this->checkoutSessionFactory->create()->setDeliveryOption([$deliveryAddressId => $selectedDeliveryOption]);
+            } elseif ($hadSelectedDeliveryOption && $deliveryAddressId > 0) {
+                $this->context->cart->setDeliveryOption(null);
+            }
+
+            $cartPreview = $this->cartPresenterHelper->presentCart();
+
+            return [
+                'success' => true,
+                'delivery_options' => $deliveryOptions,
+                'delivery_option' => $selectedDeliveryOption ?: '',
+                'selected_delivery_option' => $selectedDeliveryOption ?: '',
+                'id_address_delivery' => $tempAddressId > 0 ? 0 : (int) $this->context->cart->id_address_delivery,
+                'cart_preview' => $cartPreview,
+                'totals' => $cartPreview['totals'],
+            ];
+        } finally {
+            if ($tempAddressId > 0) {
+                $tempAddress->cleanup($tempAddressId, $originalAddressId);
+            }
+        }
+    }
+
+    protected function isOwnedCheckoutAddress(int $addressId): bool
+    {
+        if ($addressId <= 0) {
+            return false;
+        }
+
+        $customerId = $this->customerResolver->resolveId();
+        if ($customerId <= 0) {
+            return false;
+        }
+
+        return \Customer::customerHasAddress($customerId, $addressId);
+    }
+}
diff --git a/src/Checkout/Ajax/Carrier/OnePageCheckoutSelectCarrierHandler.php b/src/Checkout/Ajax/Carrier/OnePageCheckoutSelectCarrierHandler.php
new file mode 100644
index 0000000..70511e7
--- /dev/null
+++ b/src/Checkout/Ajax/Carrier/OnePageCheckoutSelectCarrierHandler.php
@@ -0,0 +1,101 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class OnePageCheckoutSelectCarrierHandler
+{
+    private \Context $context;
+    private TranslatorInterface $translator;
+    private CheckoutSessionFactory $checkoutSessionFactory;
+    private CartPresenterHelper $cartPresenterHelper;
+    private TempAddressCarrierSelectionStorage $tempCarrierSelectionStorage;
+
+    public function __construct(
+        \Context $context,
+        TranslatorInterface $translator,
+        ?\DeliveryOptionsFinder $deliveryOptionsFinder = null,
+        ?CheckoutSessionFactory $checkoutSessionFactory = null,
+        ?CartPresenterHelper $cartPresenterHelper = null,
+        ?TempAddressCarrierSelectionStorage $tempCarrierSelectionStorage = null,
+    ) {
+        $this->context = $context;
+        $this->translator = $translator;
+        $this->checkoutSessionFactory = $checkoutSessionFactory ?? new CheckoutSessionFactory($context, $translator, $deliveryOptionsFinder);
+        $this->cartPresenterHelper = $cartPresenterHelper ?? new CartPresenterHelper($context);
+        $this->tempCarrierSelectionStorage = $tempCarrierSelectionStorage ?? new TempAddressCarrierSelectionStorage($context);
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     *
+     * @return array<string,mixed>
+     */
+    public function handle(array $requestParameters = []): array
+    {
+        $deliveryOption = (string) ($requestParameters['delivery_option'] ?? '');
+        if ($deliveryOption === '') {
+            return CheckoutAjaxResponse::error(
+                $this->translator->trans('Missing delivery option.', [], 'Shop.Notifications.Error'),
+                'delivery_option'
+            );
+        }
+
+        if (!\Validate::isLoadedObject($this->context->cart)) {
+            return CheckoutAjaxResponse::error(
+                $this->translator->trans('Unable to resolve the current cart.', [], 'Shop.Notifications.Error')
+            );
+        }
+
+        $originalAddressId = (int) $this->context->cart->id_address_delivery;
+        $tempAddress = new OpcTempAddress($this->context);
+        $tempAddressId = 0;
+
+        try {
+            $tempAddressId = $tempAddress->createFromRequest($requestParameters);
+            $deliveryAddressId = $tempAddressId ?: $originalAddressId;
+
+            if ($deliveryAddressId <= 0) {
+                return CheckoutAjaxResponse::error(
+                    $this->translator->trans('Unable to resolve the current delivery address.', [], 'Shop.Notifications.Error')
+                );
+            }
+
+            $this->persistCarrierSelection($deliveryAddressId, $deliveryOption);
+            $this->persistTemporaryCarrierSelection($deliveryOption, $tempAddressId > 0 && $originalAddressId <= 0);
+
+            $cartPreview = $this->cartPresenterHelper->presentCart();
+
+            return [
+                'success' => true,
+                'delivery_option' => $deliveryOption,
+                'id_address_delivery' => $tempAddressId > 0 ? 0 : $deliveryAddressId,
+                'cart_preview' => $cartPreview,
+                'totals' => $cartPreview['totals'],
+            ];
+        } finally {
+            if ($tempAddressId > 0) {
+                $tempAddress->cleanup($tempAddressId, $originalAddressId);
+            }
+        }
+    }
+
+    private function persistCarrierSelection(int $deliveryAddressId, string $deliveryOption): void
+    {
+        $this->checkoutSessionFactory->create()->setDeliveryOption([
+            $deliveryAddressId => $deliveryOption,
+        ]);
+    }
+
+    private function persistTemporaryCarrierSelection(string $deliveryOption, bool $shouldPersist): void
+    {
+        if ($shouldPersist) {
+            $this->tempCarrierSelectionStorage->save($deliveryOption);
+
+            return;
+        }
+
+        $this->tempCarrierSelectionStorage->clear();
+    }
+}
diff --git a/src/Checkout/Ajax/Carrier/TempAddressCarrierSelectionStorage.php b/src/Checkout/Ajax/Carrier/TempAddressCarrierSelectionStorage.php
new file mode 100644
index 0000000..0af2a80
--- /dev/null
+++ b/src/Checkout/Ajax/Carrier/TempAddressCarrierSelectionStorage.php
@@ -0,0 +1,44 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+class TempAddressCarrierSelectionStorage
+{
+    private const COOKIE_KEY = 'opc_selected_temp_delivery_option';
+
+    private \Context $context;
+
+    public function __construct(\Context $context)
+    {
+        $this->context = $context;
+    }
+
+    public function get(): string
+    {
+        if (!isset($this->context->cookie)) {
+            return '';
+        }
+
+        return (string) ($this->context->cookie->__get(self::COOKIE_KEY) ?: '');
+    }
+
+    public function save(string $deliveryOption): void
+    {
+        if (!isset($this->context->cookie)) {
+            return;
+        }
+
+        $this->context->cookie->__set(self::COOKIE_KEY, $deliveryOption);
+        $this->context->cookie->write();
+    }
+
+    public function clear(): void
+    {
+        if (!isset($this->context->cookie)) {
+            return;
+        }
+
+        $this->context->cookie->__unset(self::COOKIE_KEY);
+        $this->context->cookie->write();
+    }
+}
diff --git a/src/Checkout/Ajax/Customer/CheckoutCustomerContextResolver.php b/src/Checkout/Ajax/Customer/CheckoutCustomerContextResolver.php
new file mode 100644
index 0000000..a017dbe
--- /dev/null
+++ b/src/Checkout/Ajax/Customer/CheckoutCustomerContextResolver.php
@@ -0,0 +1,50 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+class CheckoutCustomerContextResolver
+{
+    private \Context $context;
+
+    public function __construct(\Context $context)
+    {
+        $this->context = $context;
+    }
+
+    public function resolve(): ?\Customer
+    {
+        if (\Validate::isLoadedObject($this->context->customer) && (int) $this->context->customer->id > 0) {
+            return $this->context->customer;
+        }
+
+        return $this->resolvePersistedCartOwner();
+    }
+
+    public function resolveId(): int
+    {
+        $customer = $this->resolve();
+
+        return $customer instanceof \Customer ? (int) $customer->id : 0;
+    }
+
+    private function resolvePersistedCartOwner(): ?\Customer
+    {
+        if (!\Validate::isLoadedObject($this->context->cart)) {
+            return null;
+        }
+
+        $cartId = (int) $this->context->cart->id;
+        if ($cartId <= 0) {
+            return null;
+        }
+
+        $freshCart = new \Cart($cartId);
+        if (!\Validate::isLoadedObject($freshCart) || (int) $freshCart->id_customer <= 0) {
+            return null;
+        }
+
+        $customer = new \Customer((int) $freshCart->id_customer);
+
+        return \Validate::isLoadedObject($customer) ? $customer : null;
+    }
+}
diff --git a/src/Checkout/Ajax/Customer/CheckoutCustomerTemplateBuilder.php b/src/Checkout/Ajax/Customer/CheckoutCustomerTemplateBuilder.php
new file mode 100644
index 0000000..92106bb
--- /dev/null
+++ b/src/Checkout/Ajax/Customer/CheckoutCustomerTemplateBuilder.php
@@ -0,0 +1,74 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+class CheckoutCustomerTemplateBuilder
+{
+    private \Context $context;
+    private CheckoutCustomerContextResolver $customerResolver;
+
+    public function __construct(
+        \Context $context,
+        ?CheckoutCustomerContextResolver $customerResolver = null,
+    ) {
+        $this->context = $context;
+        $this->customerResolver = $customerResolver ?? new CheckoutCustomerContextResolver($context);
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    public function build(): array
+    {
+        $templateCustomer = $this->resolveTemplateCustomer();
+        $customer = $this->customerResolver->resolve();
+
+        if (!$customer instanceof \Customer) {
+            return array_merge($templateCustomer, [
+                'is_logged' => false,
+                'addresses' => [],
+            ]);
+        }
+
+        return array_merge($templateCustomer, [
+            'id' => (int) $customer->id,
+            'firstname' => (string) $customer->firstname,
+            'lastname' => (string) $customer->lastname,
+            'email' => (string) $customer->email,
+            'is_guest' => (bool) $customer->isGuest(),
+            'is_logged' => (bool) $customer->isLogged(),
+            'addresses' => array_map(
+                [$this, 'normalizeAddress'],
+                (array) $customer->getSimpleAddresses((int) ($this->context->language->id ?? 0))
+            ),
+        ]);
+    }
+
+    /**
+     * @param array<string,mixed> $address
+     *
+     * @return array<string,mixed>
+     */
+    private function normalizeAddress(array $address): array
+    {
+        if (!array_key_exists('id', $address) && array_key_exists('id_address', $address)) {
+            $address['id'] = $address['id_address'];
+        }
+
+        return $address;
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    private function resolveTemplateCustomer(): array
+    {
+        if (!isset($this->context->smarty)) {
+            return [];
+        }
+
+        $templateCustomer = $this->context->smarty->getTemplateVars('customer');
+
+        return is_array($templateCustomer) ? $templateCustomer : [];
+    }
+}
diff --git a/src/Checkout/Ajax/OnePageCheckoutGuestInitHandler.php b/src/Checkout/Ajax/Customer/OnePageCheckoutGuestInitHandler.php
similarity index 96%
rename from src/Checkout/Ajax/OnePageCheckoutGuestInitHandler.php
rename to src/Checkout/Ajax/Customer/OnePageCheckoutGuestInitHandler.php
index e620cb3..832da11 100644
--- a/src/Checkout/Ajax/OnePageCheckoutGuestInitHandler.php
+++ b/src/Checkout/Ajax/Customer/OnePageCheckoutGuestInitHandler.php
@@ -145,6 +145,10 @@ public function handle(array $requestParameters): array
             );
         }
 
+        if (!$this->hasFreshPersistedCartRow()) {
+            return $this->cartSyncErrorResponse();
+        }
+
         $existingCustomerState = $this->resolveExistingCustomerState();
 
         $existingCustomerResponse = $this->handleExistingCustomer($existingCustomerState);
@@ -284,28 +288,20 @@ private function isLoadedCustomerId(int $customerId): bool
      */
     private function resolveExistingCustomerId(): int
     {
-        $contextCustomerId = (int) $this->context->customer->id;
         if (!\Validate::isLoadedObject($this->context->cart)) {
-            return $contextCustomerId;
+            return (int) $this->context->customer->id;
         }
 
-        // Read latest persisted owner before using in-memory cart value.
         $freshCartCustomerId = $this->getFreshCartCustomerId();
         if ($freshCartCustomerId > 0 && $this->isLoadedCustomerId($freshCartCustomerId)) {
             return $freshCartCustomerId;
         }
 
         if ($freshCartCustomerId > 0) {
-            // Ignore stale persisted owner and continue with current request context.
-            return $contextCustomerId > 0 ? $contextCustomerId : self::CUSTOMER_ID_NONE;
-        }
-
-        $contextCartCustomerId = (int) $this->context->cart->id_customer;
-        if ($contextCartCustomerId > 0) {
-            return $contextCartCustomerId;
+            return self::CUSTOMER_ID_NONE;
         }
 
-        return $contextCustomerId;
+        return self::CUSTOMER_ID_NONE;
     }
 
     /**
@@ -337,6 +333,20 @@ protected function getFreshCartCustomerId(): int
         return (int) $customerId;
     }
 
+    protected function hasFreshPersistedCartRow(): bool
+    {
+        if (!\Validate::isLoadedObject($this->context->cart)) {
+            return false;
+        }
+
+        $cartId = (int) $this->context->cart->id;
+        if ($cartId <= 0) {
+            return false;
+        }
+
+        return \Validate::isLoadedObject($this->loadCartById($cartId));
+    }
+
     /**
      * Guest init applies only when cart exists and has products.
      *
@@ -444,6 +454,10 @@ private function resolveGuestEmail(string $submittedEmail, ExistingCustomerState
             return null;
         }
 
+        if (!$existingCustomerState->hasCustomer()) {
+            return null;
+        }
+
         if (!$existingCustomerState->isGuestCustomer()) {
             return $this->resolveEmailForNonGuest($submittedEmail, $existingCustomerId);
         }
@@ -501,7 +515,7 @@ private function resolveEmailForNonGuest(string $submittedEmail, int $existingCu
         }
 
         if ($existingCustomerId === self::CUSTOMER_ID_NONE) {
-            return $this->successResponse();
+            return null;
         }
 
         // Keep current owner if email points to another account.
diff --git a/src/Checkout/Ajax/OnePageCheckoutAddressFormHandler.php b/src/Checkout/Ajax/OnePageCheckoutAddressFormHandler.php
deleted file mode 100644
index 08d3b78..0000000
--- a/src/Checkout/Ajax/OnePageCheckoutAddressFormHandler.php
+++ /dev/null
@@ -1,48 +0,0 @@
-<?php
-
-/**
- * Module AJAX handler for OPC address form refresh.
- */
-
-namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
-
-use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutForm;
-
-class OnePageCheckoutAddressFormHandler
-{
-    /**
-     * @var OnePageCheckoutForm
-     */
-    private $opcForm;
-
-    public function __construct(OnePageCheckoutForm $opcForm)
-    {
-        $this->opcForm = $opcForm;
-    }
-
-    /**
-     * @param array<string,mixed> $requestParameters
-     *
-     * @return array<string,mixed>
-     */
-    public function getTemplateVariables(array $requestParameters): array
-    {
-        if (isset($requestParameters['id_address']) && (int) $requestParameters['id_address'] > 0) {
-            $this->opcForm->fillFromAddress(new \Address((int) $requestParameters['id_address'], \Context::getContext()->language->id));
-        }
-
-        $formParams = [];
-
-        foreach (['id_country', 'invoice_id_country', 'use_same_address'] as $name) {
-            if (isset($requestParameters[$name])) {
-                $formParams[$name] = $requestParameters[$name];
-            }
-        }
-
-        if (!empty($formParams)) {
-            $this->opcForm->fillWith($formParams);
-        }
-
-        return $this->opcForm->getTemplateVariables();
-    }
-}
diff --git a/src/Checkout/Ajax/Payment/OnePageCheckoutPaymentMethodsHandler.php b/src/Checkout/Ajax/Payment/OnePageCheckoutPaymentMethodsHandler.php
new file mode 100644
index 0000000..5437f75
--- /dev/null
+++ b/src/Checkout/Ajax/Payment/OnePageCheckoutPaymentMethodsHandler.php
@@ -0,0 +1,261 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+use PrestaShop\Module\PsOnePageCheckout\Checkout\PaymentSelectionKeyBuilder;
+
+class OnePageCheckoutPaymentMethodsHandler
+{
+    private \Context $context;
+    private \PaymentOptionsFinder $paymentOptionsFinder;
+    private PaymentSelectionKeyBuilder $selectionKeyBuilder;
+
+    public function __construct(
+        \Context $context,
+        ?\PaymentOptionsFinder $paymentOptionsFinder = null,
+        ?PaymentSelectionKeyBuilder $selectionKeyBuilder = null,
+    ) {
+        $this->context = $context;
+        $this->paymentOptionsFinder = $paymentOptionsFinder ?? new \PaymentOptionsFinder();
+        $this->selectionKeyBuilder = $selectionKeyBuilder ?? new PaymentSelectionKeyBuilder();
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     *
+     * @return array<string,mixed>
+     */
+    public function handle(array $requestParameters = []): array
+    {
+        if (!\Validate::isLoadedObject($this->context->cart)) {
+            return CheckoutAjaxResponse::error('Unable to load cart.');
+        }
+
+        $originalCountry = $this->context->country;
+        $resolvedCountry = null;
+        $taxAddressType = (string) \Configuration::get('PS_TAX_ADDRESS_TYPE');
+        $addressIds = $this->resolveCountryAddressCandidates($taxAddressType, $requestParameters);
+
+        foreach ($addressIds as $addressId) {
+            $resolvedCountry = $this->loadCountryFromAddressId($addressId);
+            if ($resolvedCountry instanceof \Country) {
+                break;
+            }
+        }
+
+        if (!$resolvedCountry instanceof \Country) {
+            if ($taxAddressType === 'id_address_invoice') {
+                $resolvedCountryId = (int) ($requestParameters['invoice_id_country'] ?? 0) ?: (int) ($requestParameters['id_country'] ?? 0);
+            } else {
+                $resolvedCountryId = (int) ($requestParameters['id_country'] ?? 0) ?: (int) ($requestParameters['delivery_id_country'] ?? 0);
+            }
+
+            if ($resolvedCountryId > 0) {
+                $candidateCountry = new \Country($resolvedCountryId);
+                if (\Validate::isLoadedObject($candidateCountry)) {
+                    $resolvedCountry = $candidateCountry;
+                }
+            }
+        }
+
+        $countryId = $resolvedCountry instanceof \Country
+            ? (int) $resolvedCountry->id
+            : (\Validate::isLoadedObject($this->context->country) ? (int) $this->context->country->id : 0);
+
+        try {
+            if ($resolvedCountry instanceof \Country) {
+                $this->context->country = $resolvedCountry;
+            }
+
+            $isFree = 0.0 == (float) $this->context->cart->getOrderTotal(true, \Cart::BOTH);
+            $paymentOptions = $this->paymentOptionsFinder->present($isFree);
+            $paymentOptions = $this->filterByCountry($paymentOptions, $countryId);
+            $paymentOptions = $this->selectionKeyBuilder->enrichPaymentOptions($paymentOptions);
+            [$selectedPaymentModule, $selectedPaymentSelectionKey] = $this->resolvePersistedSelection($paymentOptions);
+
+            return [
+                'success' => true,
+                'payment_options' => $paymentOptions,
+                'is_free' => $isFree,
+                'selected_payment_module' => $selectedPaymentModule,
+                'selected_payment_selection_key' => $selectedPaymentSelectionKey,
+            ];
+        } finally {
+            $this->context->country = $originalCountry;
+        }
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     *
+     * @return int[]
+     */
+    private function resolveCountryAddressCandidates(string $taxAddressType, array $requestParameters): array
+    {
+        $requestAddressKey = $taxAddressType === 'id_address_invoice'
+            ? 'id_address_invoice'
+            : 'id_address_delivery';
+        $requestAddressId = (int) ($requestParameters[$requestAddressKey] ?? 0);
+        $cartAddressId = (int) ($this->context->cart->{$taxAddressType} ?? 0);
+
+        $addressIds = [];
+        if ($requestAddressId > 0) {
+            $addressIds[] = $requestAddressId;
+        }
+
+        if ($cartAddressId > 0 && $cartAddressId !== $requestAddressId) {
+            $addressIds[] = $cartAddressId;
+        }
+
+        return $addressIds;
+    }
+
+    private function loadCountryFromAddressId(int $addressId): ?\Country
+    {
+        if ($addressId <= 0) {
+            return null;
+        }
+
+        $address = new \Address($addressId);
+        if (!\Validate::isLoadedObject($address) || (int) $address->id_country <= 0) {
+            return null;
+        }
+
+        $candidateCountry = new \Country((int) $address->id_country);
+        if (!\Validate::isLoadedObject($candidateCountry)) {
+            return null;
+        }
+
+        return $candidateCountry;
+    }
+
+    /**
+     * @param array<int|string, mixed> $paymentOptions
+     *
+     * @return array<int|string, mixed>
+     */
+    private function filterByCountry(array $paymentOptions, int $countryId): array
+    {
+        if ($paymentOptions === [] || $countryId <= 0) {
+            return $paymentOptions;
+        }
+
+        $moduleNames = array_keys($paymentOptions);
+        $rows = \Db::getInstance()->executeS(
+            'SELECT m.`name`, mc.`id_country`
+             FROM `' . _DB_PREFIX_ . 'module` m
+             INNER JOIN `' . _DB_PREFIX_ . 'module_country` mc ON mc.`id_module` = m.`id_module`
+             WHERE mc.`id_shop` = ' . (int) $this->context->shop->id . '
+             AND m.`name` IN (\'' . implode("','", array_map('pSQL', $moduleNames)) . '\')'
+        );
+
+        if ($rows === false) {
+            return $paymentOptions;
+        }
+
+        $hasRestriction = [];
+        $allowedForCountry = [];
+        foreach ($rows as $row) {
+            $moduleName = (string) ($row['name'] ?? '');
+            if ($moduleName === '') {
+                continue;
+            }
+
+            $hasRestriction[$moduleName] = true;
+            if ((int) $row['id_country'] === $countryId) {
+                $allowedForCountry[$moduleName] = true;
+            }
+        }
+
+        return array_filter(
+            $paymentOptions,
+            static function ($moduleName) use ($hasRestriction, $allowedForCountry): bool {
+                return !isset($hasRestriction[$moduleName]) || isset($allowedForCountry[$moduleName]);
+            },
+            ARRAY_FILTER_USE_KEY
+        );
+    }
+
+    private function getSelectedPaymentModule(): string
+    {
+        if (!isset($this->context->cookie)) {
+            return '';
+        }
+
+        return (string) ($this->context->cookie->__get('opc_selected_payment_module') ?: '');
+    }
+
+    private function getSelectedPaymentSelectionKey(): string
+    {
+        if (!isset($this->context->cookie)) {
+            return '';
+        }
+
+        return (string) ($this->context->cookie->__get('opc_selected_payment_selection_key') ?: '');
+    }
+
+    /**
+     * @param array<int|string, mixed> $paymentOptions
+     *
+     * @return array{0:string,1:string}
+     */
+    private function resolvePersistedSelection(array $paymentOptions): array
+    {
+        $selectedPaymentModule = $this->getSelectedPaymentModule();
+        $selectedPaymentSelectionKey = $this->getSelectedPaymentSelectionKey();
+
+        if ($selectedPaymentModule === '' && $selectedPaymentSelectionKey === '') {
+            return ['', ''];
+        }
+
+        if ($this->hasValidPersistedSelection($paymentOptions, $selectedPaymentSelectionKey, $selectedPaymentModule)) {
+            return [$selectedPaymentModule, $selectedPaymentSelectionKey];
+        }
+
+        $this->clearPersistedSelection();
+
+        return ['', ''];
+    }
+
+    /**
+     * @param array<int|string, mixed> $paymentOptions
+     */
+    private function hasValidPersistedSelection(
+        array $paymentOptions,
+        string $selectedPaymentSelectionKey,
+        string $selectedPaymentModule,
+    ): bool {
+        if ($selectedPaymentSelectionKey !== '') {
+            foreach ($paymentOptions as $moduleOptions) {
+                if (!is_array($moduleOptions)) {
+                    continue;
+                }
+
+                foreach ($moduleOptions as $paymentOption) {
+                    if (
+                        is_array($paymentOption)
+                        && (string) ($paymentOption['selection_key'] ?? '') === $selectedPaymentSelectionKey
+                    ) {
+                        return true;
+                    }
+                }
+            }
+
+            return false;
+        }
+
+        return $selectedPaymentModule !== '' && array_key_exists($selectedPaymentModule, $paymentOptions);
+    }
+
+    private function clearPersistedSelection(): void
+    {
+        if (!isset($this->context->cookie)) {
+            return;
+        }
+
+        $this->context->cookie->__unset('opc_selected_payment_option');
+        $this->context->cookie->__unset('opc_selected_payment_module');
+        $this->context->cookie->__unset('opc_selected_payment_selection_key');
+        $this->context->cookie->write();
+    }
+}
diff --git a/src/Checkout/Ajax/Payment/OnePageCheckoutSelectPaymentHandler.php b/src/Checkout/Ajax/Payment/OnePageCheckoutSelectPaymentHandler.php
new file mode 100644
index 0000000..4afde7d
--- /dev/null
+++ b/src/Checkout/Ajax/Payment/OnePageCheckoutSelectPaymentHandler.php
@@ -0,0 +1,51 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+class OnePageCheckoutSelectPaymentHandler
+{
+    private \Context $context;
+
+    public function __construct(\Context $context)
+    {
+        $this->context = $context;
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     *
+     * @return array<string,mixed>
+     */
+    public function handle(array $requestParameters = []): array
+    {
+        $paymentOption = $requestParameters['payment_option'] ?? null;
+        $paymentModule = $requestParameters['payment_module'] ?? null;
+        $paymentSelectionKey = $requestParameters['payment_selection_key'] ?? null;
+
+        if ($this->hasMissingPaymentSelectionPayload($paymentOption, $paymentModule, $paymentSelectionKey)) {
+            return CheckoutAjaxResponse::error('Missing payment selection payload');
+        }
+
+        $this->context->cookie->__set('opc_selected_payment_option', $paymentOption);
+        $this->context->cookie->__set('opc_selected_payment_module', $paymentModule);
+        $this->context->cookie->__set('opc_selected_payment_selection_key', $paymentSelectionKey);
+        $this->context->cookie->write();
+
+        return [
+            'success' => true,
+            'payment_option' => $paymentOption,
+            'payment_module' => $paymentModule,
+            'payment_selection_key' => $paymentSelectionKey,
+        ];
+    }
+
+    private function hasMissingPaymentSelectionPayload($paymentOption, $paymentModule, $paymentSelectionKey): bool
+    {
+        return !is_string($paymentOption)
+            || $paymentOption === ''
+            || !is_string($paymentModule)
+            || $paymentModule === ''
+            || !is_string($paymentSelectionKey)
+            || $paymentSelectionKey === '';
+    }
+}
diff --git a/src/Checkout/Ajax/Shared/CartPresenterHelper.php b/src/Checkout/Ajax/Shared/CartPresenterHelper.php
new file mode 100644
index 0000000..482363d
--- /dev/null
+++ b/src/Checkout/Ajax/Shared/CartPresenterHelper.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+use PrestaShop\PrestaShop\Adapter\Presenter\Cart\CartLazyArray;
+use PrestaShop\PrestaShop\Adapter\Presenter\Cart\CartPresenter;
+
+class CartPresenterHelper
+{
+    private \Context $context;
+
+    public function __construct(\Context $context)
+    {
+        $this->context = $context;
+    }
+
+    public function presentCart(): CartLazyArray
+    {
+        $this->context->cart->resetProductRelatedStaticCache();
+        \Cache::clean('presentedCart_*');
+
+        $cartLazyArray = (new CartPresenter())->present($this->context->cart, true);
+
+        // CartLazyArray computes values on first access and caches them.
+        // Force tax-sensitive properties now so callers that restore a temporary
+        // delivery address in a finally block get correct tax-inclusive values.
+        $cartLazyArray->offsetGet('products');
+        $cartLazyArray->offsetGet('subtotals');
+        $cartLazyArray->offsetGet('totals');
+
+        return $cartLazyArray;
+    }
+}
diff --git a/src/Checkout/Ajax/Shared/CheckoutAjaxResponse.php b/src/Checkout/Ajax/Shared/CheckoutAjaxResponse.php
new file mode 100644
index 0000000..8016865
--- /dev/null
+++ b/src/Checkout/Ajax/Shared/CheckoutAjaxResponse.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+final class CheckoutAjaxResponse
+{
+    /**
+     * @return array<string,mixed>
+     */
+    public static function error(string $message, string $field = ''): array
+    {
+        return [
+            'success' => false,
+            'errors' => [
+                $field => [$message],
+            ],
+        ];
+    }
+
+    /**
+     * @param array<string,array<int,string>> $errors
+     *
+     * @return array<string,mixed>
+     */
+    public static function validation(array $errors): array
+    {
+        return [
+            'success' => false,
+            'errors' => $errors,
+        ];
+    }
+}
diff --git a/src/Checkout/Ajax/Shared/CheckoutSessionFactory.php b/src/Checkout/Ajax/Shared/CheckoutSessionFactory.php
new file mode 100644
index 0000000..6de9e2a
--- /dev/null
+++ b/src/Checkout/Ajax/Shared/CheckoutSessionFactory.php
@@ -0,0 +1,46 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax;
+
+use PrestaShop\PrestaShop\Adapter\Presenter\Object\ObjectPresenter;
+use PrestaShop\PrestaShop\Adapter\Product\PriceFormatter;
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class CheckoutSessionFactory
+{
+    private \Context $context;
+    private TranslatorInterface $translator;
+    private ?\DeliveryOptionsFinder $deliveryOptionsFinder;
+
+    public function __construct(
+        \Context $context,
+        TranslatorInterface $translator,
+        ?\DeliveryOptionsFinder $deliveryOptionsFinder = null,
+    ) {
+        $this->context = $context;
+        $this->translator = $translator;
+        $this->deliveryOptionsFinder = $deliveryOptionsFinder;
+    }
+
+    public function create(): \CheckoutSession
+    {
+        return new \CheckoutSession(
+            $this->context,
+            $this->createDeliveryOptionsFinder()
+        );
+    }
+
+    public function createDeliveryOptionsFinder(): \DeliveryOptionsFinder
+    {
+        if ($this->deliveryOptionsFinder) {
+            return $this->deliveryOptionsFinder;
+        }
+
+        return new \DeliveryOptionsFinder(
+            $this->context,
+            $this->translator,
+            new ObjectPresenter(),
+            new PriceFormatter()
+        );
+    }
+}
diff --git a/src/Checkout/Ajax/Submit/OnePageCheckoutSubmitHandler.php b/src/Checkout/Ajax/Submit/OnePageCheckoutSubmitHandler.php
new file mode 100644
index 0000000..50bf820
--- /dev/null
+++ b/src/Checkout/Ajax/Submit/OnePageCheckoutSubmitHandler.php
@@ -0,0 +1,79 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\Submit;
+
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutSessionFactory;
+
+class OnePageCheckoutSubmitHandler
+{
+    private \Context $context;
+    private CheckoutSessionFactory $checkoutSessionFactory;
+    private OnePageCheckoutSubmitProcessor $submitProcessor;
+    private OnePageCheckoutSubmitValidationStateStorage $submitValidationStateStorage;
+
+    public function __construct(
+        \Context $context,
+        CheckoutSessionFactory $checkoutSessionFactory,
+        OnePageCheckoutSubmitProcessor $submitProcessor,
+        OnePageCheckoutSubmitValidationStateStorage $submitValidationStateStorage,
+    ) {
+        $this->context = $context;
+        $this->checkoutSessionFactory = $checkoutSessionFactory;
+        $this->submitProcessor = $submitProcessor;
+        $this->submitValidationStateStorage = $submitValidationStateStorage;
+    }
+
+    /**
+     * @param array<string, mixed> $requestParameters
+     *
+     * @return array<string, mixed>
+     */
+    public function handle(array $requestParameters): array
+    {
+        $checkoutSession = $this->checkoutSessionFactory->create();
+        $this->persistSelectedPaymentModule($requestParameters);
+        $processingResult = $this->submitProcessor->process($checkoutSession, $requestParameters);
+        if (($processingResult['success'] ?? false) === true) {
+            $this->submitValidationStateStorage->clear();
+
+            return [
+                'success' => true,
+                'reload' => false,
+                'checkout_url' => $checkoutSession->getCheckoutURL(),
+            ];
+        }
+
+        $this->submitValidationStateStorage->save([
+            'validation_errors' => isset($processingResult['validation_errors']) && is_array($processingResult['validation_errors'])
+                ? $processingResult['validation_errors']
+                : [],
+            'form_errors' => isset($processingResult['form_errors']) && is_array($processingResult['form_errors'])
+                ? $processingResult['form_errors']
+                : [],
+            'submitted_values' => isset($processingResult['submitted_values']) && is_array($processingResult['submitted_values'])
+                ? $processingResult['submitted_values']
+                : [],
+        ]);
+
+        return [
+            'success' => false,
+            'reload' => true,
+            'checkout_url' => $checkoutSession->getCheckoutURL(),
+        ];
+    }
+
+    /**
+     * @param array<string, mixed> $requestParameters
+     */
+    private function persistSelectedPaymentModule(array $requestParameters): void
+    {
+        $paymentMethod = isset($requestParameters['paymentMethod']) ? trim((string) $requestParameters['paymentMethod']) : '';
+
+        if ($paymentMethod === '' || !isset($this->context->cookie)) {
+            return;
+        }
+
+        $this->context->cookie->__set('opc_selected_payment_module', $paymentMethod);
+        $this->context->cookie->write();
+    }
+}
diff --git a/src/Checkout/Ajax/Submit/OnePageCheckoutSubmitProcessor.php b/src/Checkout/Ajax/Submit/OnePageCheckoutSubmitProcessor.php
new file mode 100644
index 0000000..97ff9e8
--- /dev/null
+++ b/src/Checkout/Ajax/Submit/OnePageCheckoutSubmitProcessor.php
@@ -0,0 +1,424 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\Submit;
+
+use PrestaShop\Module\PsOnePageCheckout\Checkout\PaymentSelectionKeyBuilder;
+use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutForm;
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class OnePageCheckoutSubmitProcessor
+{
+    private \Context $context;
+    private TranslatorInterface $translator;
+    private OnePageCheckoutForm $opcForm;
+    private \PaymentOptionsFinder $paymentOptionsFinder;
+    private \ConditionsToApproveFinder $conditionsToApproveFinder;
+    private PaymentSelectionKeyBuilder $paymentSelectionKeyBuilder;
+    /**
+     * @var array<string,mixed>
+     */
+    private array $validationErrors = [];
+
+    public function __construct(
+        \Context $context,
+        TranslatorInterface $translator,
+        OnePageCheckoutForm $opcForm,
+        \PaymentOptionsFinder $paymentOptionsFinder,
+        \ConditionsToApproveFinder $conditionsToApproveFinder,
+        ?PaymentSelectionKeyBuilder $paymentSelectionKeyBuilder = null,
+    ) {
+        $this->context = $context;
+        $this->translator = $translator;
+        $this->opcForm = $opcForm;
+        $this->paymentOptionsFinder = $paymentOptionsFinder;
+        $this->conditionsToApproveFinder = $conditionsToApproveFinder;
+        $this->paymentSelectionKeyBuilder = $paymentSelectionKeyBuilder ?? new PaymentSelectionKeyBuilder();
+    }
+
+    /**
+     * @param \CheckoutSession $checkoutSession
+     * @param array<string,mixed> $requestParameters
+     *
+     * @return array<string,mixed>
+     */
+    public function process(\CheckoutSession $checkoutSession, array $requestParameters): array
+    {
+        $this->validationErrors = [];
+        $normalizedRequestParameters = $this->normalizeSubmittedRequestParameters($requestParameters);
+
+        $this->hydrateOpcFromSubmittedAddresses($normalizedRequestParameters);
+
+        $validationResult = $this->validateAllSections($checkoutSession, $normalizedRequestParameters);
+        if (!$this->isAllSectionsValid($validationResult)) {
+            return $this->buildFailureResult($normalizedRequestParameters);
+        }
+
+        if (!$this->saveAllSections($checkoutSession, $normalizedRequestParameters)) {
+            return $this->buildFailureResult($normalizedRequestParameters);
+        }
+
+        return [
+            'success' => true,
+            'validation_errors' => [],
+            'form_errors' => [],
+            'submitted_values' => [],
+        ];
+    }
+
+    /**
+     * Browser form submits omit unchecked checkboxes, but OPC always needs an explicit
+     * same/different-address flag during the final submit flow.
+     *
+     * @param array<string,mixed> $requestParameters
+     *
+     * @return array<string,mixed>
+     */
+    private function normalizeSubmittedRequestParameters(array $requestParameters): array
+    {
+        if (!array_key_exists('use_same_address', $requestParameters)) {
+            $requestParameters['use_same_address'] = $this->context->cart->isVirtualCart() ? '1' : '0';
+        }
+
+        return $requestParameters;
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     */
+    private function hydrateOpcFromSubmittedAddresses(array $requestParameters): void
+    {
+        $deliveryAddressId = (int) ($requestParameters['id_address_delivery'] ?? 0);
+        $invoiceAddressId = (int) ($requestParameters['id_address_invoice'] ?? 0);
+        $customerId = (int) ($this->context->customer->id ?? 0);
+
+        $this->fillOpcFormFromResolvedAddresses($deliveryAddressId, $invoiceAddressId, $customerId);
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     *
+     * @return array<string,bool>
+     */
+    private function validateAllSections(\CheckoutSession $checkoutSession, array $requestParameters): array
+    {
+        return [
+            'identity' => $this->validateIdentitySection($requestParameters),
+            'address' => $this->validateAddressSection($requestParameters),
+            'shipping' => $this->validateShippingSection($checkoutSession, $requestParameters),
+            'payment' => $this->validatePaymentSection($checkoutSession, $requestParameters),
+            'conditions' => $this->validateConditionsSection($requestParameters),
+        ];
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     */
+    private function validateIdentitySection(array $requestParameters): bool
+    {
+        $customer = $this->context->customer;
+        $email = (string) ($requestParameters['email'] ?? '');
+
+        if (
+            $email === ''
+            && $customer instanceof \Customer
+            && $customer->isLogged()
+            && !$customer->isGuest()
+        ) {
+            $email = (string) $customer->email;
+        }
+
+        if ($email !== '' && \Validate::isEmail($email)) {
+            return true;
+        }
+
+        $this->validationErrors['identity'] = [
+            'email' => $this->translator->trans(
+                'Invalid email format.',
+                [],
+                'Shop.Notifications.Error'
+            ),
+        ];
+
+        return false;
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     */
+    private function validateAddressSection(array $requestParameters): bool
+    {
+        $this->opcForm->fillWith($requestParameters);
+
+        if ($this->opcForm->validate()) {
+            return true;
+        }
+
+        $this->validationErrors['address'] = $this->opcForm->getErrors();
+
+        return false;
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     */
+    private function validateShippingSection(\CheckoutSession $checkoutSession, array $requestParameters): bool
+    {
+        if ($this->context->cart->isVirtualCart()) {
+            return true;
+        }
+
+        $deliveryOptions = $checkoutSession->getDeliveryOptions();
+        $deliveryOptionKey = isset($requestParameters['delivery_option']) && is_string($requestParameters['delivery_option'])
+            ? $requestParameters['delivery_option']
+            : (string) $checkoutSession->getSelectedDeliveryOption();
+
+        if ($deliveryOptionKey === '' || empty($deliveryOptions[$deliveryOptionKey])) {
+            $this->validationErrors['shipping'] = [
+                'delivery_option' => $this->translator->trans(
+                    'Please select a shipping method.',
+                    [],
+                    'Shop.Notifications.Error'
+                ),
+            ];
+
+            return false;
+        }
+
+        $currentDeliveryOption = $deliveryOptions[$deliveryOptionKey];
+        $isComplete = true;
+
+        if (!empty($currentDeliveryOption['is_module']) && !empty($currentDeliveryOption['external_module_name'])) {
+            \Hook::exec(
+                'actionValidateStepComplete',
+                [
+                    'step_name' => 'delivery',
+                    'request_params' => $requestParameters,
+                    'completed' => &$isComplete,
+                ],
+                \Module::getModuleIdByName($currentDeliveryOption['external_module_name'])
+            );
+        }
+
+        return $isComplete;
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     */
+    private function validatePaymentSection(\CheckoutSession $checkoutSession, array $requestParameters): bool
+    {
+        $isFree = 0 == (float) $checkoutSession->getCart()->getOrderTotal(true, \Cart::BOTH);
+        $paymentOptions = $this->paymentSelectionKeyBuilder->enrichPaymentOptions(
+            (array) $this->paymentOptionsFinder->present($isFree)
+        );
+        $selectedPaymentModule = trim((string) ($requestParameters['paymentMethod'] ?? $this->getSelectedPaymentModule()));
+
+        if ($isFree || empty($paymentOptions) || $selectedPaymentModule !== '') {
+            return true;
+        }
+
+        $this->validationErrors['payment'] = [
+            'paymentMethod' => $this->translator->trans(
+                'Please select a payment method.',
+                [],
+                'Shop.Notifications.Error'
+            ),
+        ];
+
+        return false;
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     */
+    private function validateConditionsSection(array $requestParameters): bool
+    {
+        $conditionsToApprove = (array) $this->conditionsToApproveFinder->getConditionsToApproveForTemplate();
+        $submittedConditions = $requestParameters['conditions_to_approve'] ?? [];
+
+        if (!is_array($submittedConditions)) {
+            $submittedConditions = [];
+        }
+
+        foreach (array_keys($conditionsToApprove) as $conditionIdentifier) {
+            if (!empty($submittedConditions[$conditionIdentifier])) {
+                continue;
+            }
+
+            $this->validationErrors['conditions'] = [
+                'conditions_to_approve' => $this->translator->trans(
+                    'Please accept the terms of service.',
+                    [],
+                    'Shop.Notifications.Error'
+                ),
+            ];
+
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * @param array<string,bool> $validationResult
+     */
+    private function isAllSectionsValid(array $validationResult): bool
+    {
+        return $validationResult['identity']
+            && $validationResult['address']
+            && $validationResult['shipping']
+            && $validationResult['payment']
+            && $validationResult['conditions'];
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     */
+    private function saveAllSections(\CheckoutSession $checkoutSession, array $requestParameters): bool
+    {
+        $customer = $this->context->customer;
+        $isGuestFlow = !$customer->isLogged() || $customer->isGuest();
+        if ($isGuestFlow) {
+            $hookResult = array_reduce(
+                \Hook::exec('actionSubmitAccountBefore', [], null, true),
+                static function ($carry, $item) {
+                    return $carry && $item;
+                },
+                true
+            );
+            if (!$hookResult) {
+                return false;
+            }
+        }
+
+        $addressIds = $this->opcForm->fillWith($requestParameters)->submit();
+        if (!$addressIds) {
+            $this->validationErrors['address'] = $this->opcForm->getErrors();
+
+            return false;
+        }
+
+        $checkoutSession->setIdAddressDelivery($addressIds['id_address_delivery']);
+        $checkoutSession->setIdAddressInvoice($addressIds['id_address_invoice']);
+
+        if (
+            !$this->context->cart->isVirtualCart()
+            && isset($requestParameters['delivery_option'])
+            && is_string($requestParameters['delivery_option'])
+            && $requestParameters['delivery_option'] !== ''
+        ) {
+            $checkoutSession->setDeliveryOption([
+                (int) $addressIds['id_address_delivery'] => $requestParameters['delivery_option'],
+            ]);
+        }
+
+        if (isset($requestParameters['delivery_message'])) {
+            $checkoutSession->setMessage($requestParameters['delivery_message']);
+        }
+
+        if ((bool) \Configuration::get('PS_RECYCLABLE_PACK')) {
+            $checkoutSession->setRecyclable($requestParameters['recyclable'] ?? false);
+        }
+
+        if ((bool) \Configuration::get('PS_GIFT_WRAPPING')) {
+            $useGift = $requestParameters['gift'] ?? false;
+            $checkoutSession->setGift(
+                $useGift,
+                $useGift ? ($requestParameters['gift_message'] ?? '') : ''
+            );
+        }
+
+        $customer = $checkoutSession->getCustomer();
+        if ($customer->isGuest() || empty($customer->firstname) || empty($customer->lastname)) {
+            $address = new \Address($addressIds['id_address_delivery'], (int) $this->context->language->id);
+            if ($address->id && (!empty($address->firstname) || !empty($address->lastname))) {
+                $customer->firstname = $address->firstname;
+                $customer->lastname = $address->lastname;
+                $customer->save();
+                $this->context->updateCustomer($customer);
+            }
+        }
+
+        \Hook::exec('actionCarrierProcess', ['cart' => $checkoutSession->getCart()]);
+
+        return true;
+    }
+
+    /**
+     * @param array<string,mixed> $submittedValues
+     *
+     * @return array<string,mixed>
+     */
+    private function buildFailureResult(array $submittedValues): array
+    {
+        return [
+            'success' => false,
+            'validation_errors' => $this->validationErrors,
+            'form_errors' => $this->opcForm->getErrors(),
+            'submitted_values' => $this->filterPersistedSubmittedValues($submittedValues),
+        ];
+    }
+
+    /**
+     * @param array<string,mixed> $submittedValues
+     *
+     * @return array<string,mixed>
+     */
+    private function filterPersistedSubmittedValues(array $submittedValues): array
+    {
+        unset(
+            $submittedValues['ajax'],
+            $submittedValues['action'],
+            $submittedValues['static_token'],
+            $submittedValues['token'],
+            $submittedValues['paymentMethod']
+        );
+
+        return array_filter(
+            $submittedValues,
+            static fn ($value): bool => is_scalar($value) || is_array($value) || $value === null
+        );
+    }
+
+    private function getSelectedPaymentModule(): string
+    {
+        if (!isset($this->context->cookie)) {
+            return '';
+        }
+
+        return (string) ($this->context->cookie->__get('opc_selected_payment_module') ?: '');
+    }
+
+    private function fillOpcFormFromResolvedAddresses(int $deliveryAddressId, int $invoiceAddressId, ?int $customerId = null): void
+    {
+        if ($deliveryAddressId <= 0 && $invoiceAddressId <= 0) {
+            return;
+        }
+
+        $languageId = (int) $this->context->language->id;
+        $deliveryAddress = $this->resolveAddressForHydration($deliveryAddressId, $languageId, $customerId);
+        $invoiceAddress = null;
+
+        if ($invoiceAddressId > 0 && $invoiceAddressId !== $deliveryAddressId) {
+            $invoiceAddress = $this->resolveAddressForHydration($invoiceAddressId, $languageId, $customerId);
+        }
+
+        if ($deliveryAddress || $invoiceAddress) {
+            $this->opcForm->fillFromAddresses($deliveryAddress, $invoiceAddress);
+        }
+    }
+
+    private function resolveAddressForHydration(int $addressId, int $languageId, ?int $customerId = null): ?\Address
+    {
+        if (
+            $addressId <= 0
+            || ($customerId !== null && ($customerId <= 0 || !\Customer::customerHasAddress($customerId, $addressId)))
+        ) {
+            return null;
+        }
+
+        $address = new \Address($addressId, $languageId);
+
+        return \Validate::isLoadedObject($address) ? $address : null;
+    }
+}
diff --git a/src/Checkout/Ajax/Submit/OnePageCheckoutSubmitValidationStateStorage.php b/src/Checkout/Ajax/Submit/OnePageCheckoutSubmitValidationStateStorage.php
new file mode 100644
index 0000000..e50527a
--- /dev/null
+++ b/src/Checkout/Ajax/Submit/OnePageCheckoutSubmitValidationStateStorage.php
@@ -0,0 +1,81 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\Submit;
+
+class OnePageCheckoutSubmitValidationStateStorage
+{
+    private const COOKIE_KEY = 'opc_submit_validation_state';
+
+    private \Context $context;
+
+    public function __construct(\Context $context)
+    {
+        $this->context = $context;
+    }
+
+    /**
+     * @param array<string,mixed> $state
+     */
+    public function save(array $state): void
+    {
+        if (!$this->hasCookie()) {
+            return;
+        }
+
+        $encodedState = json_encode($state);
+        if ($encodedState === false) {
+            return;
+        }
+
+        $this->context->cookie->__set(self::COOKIE_KEY, $encodedState);
+        $this->writeCookie();
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    public function consume(): array
+    {
+        if (!$this->hasCookie()) {
+            return [];
+        }
+
+        $rawState = (string) ($this->context->cookie->__get(self::COOKIE_KEY) ?: '');
+        $this->clear();
+
+        if ($rawState === '') {
+            return [];
+        }
+
+        $decodedState = json_decode($rawState, true);
+
+        return is_array($decodedState) ? $decodedState : [];
+    }
+
+    public function clear(): void
+    {
+        if (!$this->hasCookie()) {
+            return;
+        }
+
+        if (method_exists($this->context->cookie, '__unset')) {
+            $this->context->cookie->__unset(self::COOKIE_KEY);
+        } else {
+            $this->context->cookie->__set(self::COOKIE_KEY, '');
+        }
+
+        $this->writeCookie();
+    }
+
+    private function hasCookie(): bool
+    {
+        return isset($this->context->cookie);
+    }
+
+    private function writeCookie(): void
+    {
+        if (method_exists($this->context->cookie, 'write')) {
+            $this->context->cookie->write();
+        }
+    }
+}
diff --git a/src/Checkout/CheckoutOnePageStep.php b/src/Checkout/CheckoutOnePageStep.php
index 37d31f4..3bbe6ce 100644
--- a/src/Checkout/CheckoutOnePageStep.php
+++ b/src/Checkout/CheckoutOnePageStep.php
@@ -27,10 +27,9 @@
 
 namespace PrestaShop\Module\PsOnePageCheckout\Checkout;
 
-use Address;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\Submit\OnePageCheckoutSubmitValidationStateStorage;
 use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutForm;
 use Symfony\Contracts\Translation\TranslatorInterface;
-use Validate;
 
 class CheckoutOnePageStep extends \AbstractCheckoutStep
 {
@@ -46,6 +45,8 @@ class CheckoutOnePageStep extends \AbstractCheckoutStep
      */
     public $paymentOptionsFinder;
 
+    private PaymentSelectionKeyBuilder $paymentSelectionKeyBuilder;
+
     /**
      * @var \ConditionsToApproveFinder
      */
@@ -59,6 +60,8 @@ class CheckoutOnePageStep extends \AbstractCheckoutStep
     private $displayTaxesLabel = false;
 
     private $validationErrors = [];
+    private bool $clearPersistedValidationErrorsOnNextSave = false;
+    private OnePageCheckoutSubmitValidationStateStorage $submitValidationStateStorage;
 
     /**
      * @param \Context $context
@@ -66,6 +69,7 @@ class CheckoutOnePageStep extends \AbstractCheckoutStep
      * @param OnePageCheckoutForm $opcForm
      * @param \PaymentOptionsFinder $paymentOptionsFinder
      * @param \ConditionsToApproveFinder $conditionsToApproveFinder
+     * @param PaymentSelectionKeyBuilder|null $paymentSelectionKeyBuilder
      */
     public function __construct(
         \Context $context,
@@ -73,11 +77,15 @@ public function __construct(
         OnePageCheckoutForm $opcForm,
         \PaymentOptionsFinder $paymentOptionsFinder,
         \ConditionsToApproveFinder $conditionsToApproveFinder,
+        ?PaymentSelectionKeyBuilder $paymentSelectionKeyBuilder = null,
+        ?OnePageCheckoutSubmitValidationStateStorage $submitValidationStateStorage = null,
     ) {
         parent::__construct($context, $translator);
         $this->opcForm = $opcForm;
         $this->paymentOptionsFinder = $paymentOptionsFinder;
         $this->conditionsToApproveFinder = $conditionsToApproveFinder;
+        $this->paymentSelectionKeyBuilder = $paymentSelectionKeyBuilder ?? new PaymentSelectionKeyBuilder();
+        $this->submitValidationStateStorage = $submitValidationStateStorage ?? new OnePageCheckoutSubmitValidationStateStorage($context);
     }
 
     // Delivery options setters (like CheckoutDeliveryStep)
@@ -146,14 +154,15 @@ public function handleRequest(array $requestParameters = [])
         // Step is always reachable (single step)
         $this->setReachable(true);
 
-        // Pre-fill form from session if not submitting
-        if (!isset($requestParameters['submitOnePageCheckout'])) {
-            $this->hydrateOpcFromSession();
-        }
+        $this->hydrateOpcFromSession();
+        $this->restoreLastFailedSubmitState();
 
-        // Handle submission
-        if (isset($requestParameters['submitOnePageCheckout'])) {
-            $this->handleOnePageCheckoutSubmit($requestParameters);
+        if (
+            !$this->context->cart->isVirtualCart()
+            && isset($requestParameters['delivery_option'])
+            && is_array($requestParameters['delivery_option'])
+        ) {
+            $this->getCheckoutSession()->setDeliveryOption($requestParameters['delivery_option']);
         }
 
         $this->setTitle(
@@ -174,169 +183,65 @@ private function hydrateOpcFromSession(): void
             $this->opcForm->fillFromCustomer($customer);
         }
 
-        $languageId = $this->context->language->id;
-
-        $idAddressDelivery = $session->getIdAddressDelivery();
-        $idAddressInvoice = $session->getIdAddressInvoice();
-
-        $deliveryAddress = $idAddressDelivery ? new \Address($idAddressDelivery, $languageId) : null;
-
-        $invoiceAddress = null;
-        if ($idAddressInvoice && $idAddressInvoice != $idAddressDelivery) {
-            $invoiceAddress = new \Address($idAddressInvoice, $languageId);
-        }
-
-        if ($deliveryAddress || $invoiceAddress) {
-            $this->opcForm->fillFromAddresses($deliveryAddress, $invoiceAddress);
-        }
-    }
-
-    private function handleOnePageCheckoutSubmit(array $requestParameters): void
-    {
-        $validationResult = $this->validateAllSections($requestParameters);
-        if (!$this->isAllSectionsValid($validationResult)) {
-            $this->getCheckoutProcess()->setHasErrors(true);
-            $this->setCurrent(true);
-
-            return;
-        }
-        if (!$this->saveAllSections($requestParameters)) {
-            $this->getCheckoutProcess()->setHasErrors(true);
-
-            return;
-        }
-        $this->setComplete(true);
+        $this->fillOpcFormFromResolvedAddresses(
+            (int) $session->getIdAddressDelivery(),
+            (int) $session->getIdAddressInvoice()
+        );
     }
 
     /**
-     * Validate all sections (5 validations)
-     *
-     * @param array $requestParameters
+     * Get validation errors
      *
-     * @return array ['identity' => bool, 'address' => bool, 'shipping' => bool, 'payment' => bool, 'conditions' => bool]
+     * @return array
      */
-    private function validateAllSections(array $requestParameters)
+    public function getValidationErrors()
     {
-        $this->validationErrors = [];
-        $result = [
-            'identity' => true,
-            'address' => true,
-            'shipping' => true,
-            'payment' => true,
-            'conditions' => true,
-        ];
-
-        // 1. Identity validation: email only
-        if (empty($requestParameters['email']) || !\Validate::isEmail($requestParameters['email'])) {
-            $result['identity'] = false;
-            $this->validationErrors['identity'] = [
-                'email' => $this->getTranslator()->trans(
-                    'Invalid email format.',
-                    [],
-                    'Shop.Notifications.Error'
-                ),
-            ];
-        }
-
-        // 2. Address validation: validate form
-        $this->opcForm->fillWith($requestParameters);
-        if (!$this->opcForm->validate()) {
-            $result['address'] = false;
-            $this->validationErrors['address'] = $this->opcForm->getErrors();
-        }
-
-        return $result;
+        return $this->validationErrors;
     }
 
     /**
-     * Check if all sections are valid
-     *
-     * @param array $validationResult
-     *
-     * @return bool
+     * @return array<string,mixed>
      */
-    private function isAllSectionsValid(array $validationResult)
+    public function getDataToPersist()
     {
-        return $validationResult['identity']
-            && $validationResult['address']
-            && $validationResult['shipping']
-            && $validationResult['payment']
-            && $validationResult['conditions'];
+        // This step still lives inside the Core CheckoutProcess injected by the module hook,
+        // so it must keep the standard AbstractCheckoutStep persistence contract.
+        return [
+            'validation_errors' => $this->clearPersistedValidationErrorsOnNextSave ? [] : $this->validationErrors,
+        ];
     }
 
     /**
-     * Save all sections (5 saves)
-     *
-     * @param array $requestParameters
+     * Keep step identifier stable to avoid persistence regressions in checkout_session_data.
      *
-     * @return bool
+     * @return string
      */
-    private function saveAllSections(array $requestParameters)
+    public function getIdentifier()
     {
-        // 1. Identity + Address: save via form (creates/updates customer guest and addresses)
-        $customer = $this->context->customer;
-        $isGuestFlow = !$customer->isLogged() || $customer->isGuest();
-        if ($isGuestFlow) {
-            $hookResult = array_reduce(
-                \Hook::exec('actionSubmitAccountBefore', [], null, true),
-                function ($carry, $item) {
-                    return $carry && $item;
-                },
-                true
-            );
-            if (!$hookResult) {
-                return false;
-            }
-        }
-
-        $addressIds = $this->opcForm->fillWith($requestParameters)->submit();
-        if (!$addressIds) {
-            return false;
-        }
-
-        // Set addresses in session
-        $this->getCheckoutSession()->setIdAddressDelivery($addressIds['id_address_delivery']);
-        $this->getCheckoutSession()->setIdAddressInvoice($addressIds['id_address_invoice']);
-
-        // Sync customer name from delivery address if needed
-        $customer = $this->getCheckoutSession()->getCustomer();
-        if ($customer && ($customer->isGuest() || empty($customer->firstname) || empty($customer->lastname))) {
-            $address = new \Address($addressIds['id_address_delivery'], $this->context->language->id);
-            if ($address->id && (!empty($address->firstname) || !empty($address->lastname))) {
-                $customer->firstname = $address->firstname;
-                $customer->lastname = $address->lastname;
-                $customer->save();
-                $this->context->updateCustomer($customer);
-            }
-        }
-
-        return true;
+        return 'checkout-one-page-step';
     }
 
     /**
-     * Get validation errors
+     * @param array<string,mixed> $data
      *
-     * @return array
+     * @return $this
      */
-    public function getValidationErrors()
+    public function restorePersistedData(array $data)
     {
-        return $this->validationErrors;
-    }
+        $this->validationErrors = isset($data['validation_errors']) && is_array($data['validation_errors'])
+            ? $data['validation_errors']
+            : [];
+        $this->clearPersistedValidationErrorsOnNextSave = !empty($this->validationErrors);
 
-    /**
-     * Keep step identifier stable to avoid persistence regressions in checkout_session_data.
-     *
-     * @return string
-     */
-    public function getIdentifier()
-    {
-        return 'checkout-one-page-step';
+        return $this;
     }
 
     public function render(array $extraParams = [])
     {
         $isFree = 0 == (float) $this->getCheckoutSession()->getCart()->getOrderTotal(true, \Cart::BOTH);
-        $paymentOptions = $this->paymentOptionsFinder->present($isFree);
+        $paymentOptions = $this->paymentSelectionKeyBuilder->enrichPaymentOptions(
+            $this->paymentOptionsFinder->present($isFree)
+        );
         $conditionsToApprove = $this->conditionsToApproveFinder->getConditionsToApproveForTemplate();
         $deliveryOptions = $this->getCheckoutSession()->getDeliveryOptions();
         $deliveryOptionKey = $this->getCheckoutSession()->getSelectedDeliveryOption();
@@ -352,15 +257,18 @@ public function render(array $extraParams = [])
         }
 
         $assignedVars = [
-            'opc_form' => $this->opcForm->getProxy(),
             'hookDisplayBeforeCarrier' => \Hook::exec('displayBeforeCarrier', ['cart' => $this->getCheckoutSession()->getCart()]),
             'hookDisplayAfterCarrier' => \Hook::exec('displayAfterCarrier', ['cart' => $this->getCheckoutSession()->getCart()]),
             'delivery_options' => $deliveryOptions,
             'delivery_option' => $deliveryOptionKey,
             'selected_delivery_option' => $selectedDeliveryOption,
             'payment_options' => $paymentOptions,
+            'is_free' => $isFree,
+            'selected_payment_module' => $this->getSelectedPaymentModule(),
+            'selected_payment_selection_key' => $this->getSelectedPaymentSelectionKey(),
             'conditions_to_approve' => $conditionsToApprove,
             'validation_errors' => $this->validationErrors,
+            'validation_error_messages' => $this->getValidationErrorMessages(),
             'recyclable' => $this->getCheckoutSession()->isRecyclable(),
             'recyclablePackAllowed' => $this->isRecyclablePackAllowed(),
             'delivery_message' => $this->getCheckoutSession()->getMessage(),
@@ -370,8 +278,122 @@ public function render(array $extraParams = [])
                 'message' => $this->getCheckoutSession()->getGift()['message'],
             ],
             'is_virtual_cart' => $this->context->cart->isVirtualCart(),
-        ];
+            'configuration' => $this->getTemplateConfiguration(),
+        ] + $this->opcForm->getTemplateVariables();
 
         return $this->renderTemplate($this->getTemplate(), $extraParams, $assignedVars);
     }
+
+    private function getSelectedPaymentModule(): string
+    {
+        if (!isset($this->context->cookie)) {
+            return '';
+        }
+
+        return (string) ($this->context->cookie->__get('opc_selected_payment_module') ?: '');
+    }
+
+    private function getSelectedPaymentSelectionKey(): string
+    {
+        if (!isset($this->context->cookie)) {
+            return '';
+        }
+
+        return (string) ($this->context->cookie->__get('opc_selected_payment_selection_key') ?: '');
+    }
+
+    private function restoreLastFailedSubmitState(): void
+    {
+        $submitState = $this->submitValidationStateStorage->consume();
+        if ($submitState === []) {
+            return;
+        }
+
+        $submittedValues = isset($submitState['submitted_values']) && is_array($submitState['submitted_values'])
+            ? $submitState['submitted_values']
+            : [];
+        $formErrors = isset($submitState['form_errors']) && is_array($submitState['form_errors'])
+            ? $submitState['form_errors']
+            : [];
+
+        if ($submittedValues !== [] || $formErrors !== []) {
+            $this->opcForm->restoreSubmissionState($submittedValues, $formErrors);
+        }
+
+        $this->validationErrors = isset($submitState['validation_errors']) && is_array($submitState['validation_errors'])
+            ? $submitState['validation_errors']
+            : [];
+
+        if ($this->validationErrors !== [] || $formErrors !== []) {
+            $this->clearPersistedValidationErrorsOnNextSave = true;
+        }
+    }
+
+    /**
+     * @return array<int,string>
+     */
+    private function getValidationErrorMessages(): array
+    {
+        $messages = [];
+
+        array_walk_recursive($this->validationErrors, static function ($value) use (&$messages): void {
+            if (!is_string($value) || $value === '') {
+                return;
+            }
+
+            $messages[] = $value;
+        });
+
+        return array_values(array_unique($messages));
+    }
+
+    private function fillOpcFormFromResolvedAddresses(int $deliveryAddressId, int $invoiceAddressId, ?int $customerId = null): void
+    {
+        if ($deliveryAddressId <= 0 && $invoiceAddressId <= 0) {
+            return;
+        }
+
+        $languageId = (int) $this->context->language->id;
+        $deliveryAddress = $this->resolveAddressForHydration($deliveryAddressId, $languageId, $customerId);
+        $invoiceAddress = null;
+
+        if ($invoiceAddressId > 0 && $invoiceAddressId !== $deliveryAddressId) {
+            $invoiceAddress = $this->resolveAddressForHydration($invoiceAddressId, $languageId, $customerId);
+        }
+
+        if ($deliveryAddress || $invoiceAddress) {
+            $this->opcForm->fillFromAddresses($deliveryAddress, $invoiceAddress);
+        }
+    }
+
+    private function resolveAddressForHydration(int $addressId, int $languageId, ?int $customerId = null): ?\Address
+    {
+        if (
+            $addressId <= 0
+            || ($customerId !== null && ($customerId <= 0 || !\Customer::customerHasAddress($customerId, $addressId)))
+        ) {
+            return null;
+        }
+
+        $address = new \Address($addressId, $languageId);
+
+        return \Validate::isLoadedObject($address) ? $address : null;
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    private function getTemplateConfiguration(): array
+    {
+        $configuration = [];
+        $controller = $this->context->controller ?? null;
+
+        if (is_object($controller) && method_exists($controller, 'getTemplateVarConfiguration')) {
+            $configuration = (array) $controller->getTemplateVarConfiguration();
+        }
+
+        $configuration['is_guest_checkout_enabled'] = (bool) \Configuration::get('PS_GUEST_CHECKOUT_ENABLED');
+
+        return $configuration;
+    }
 }
diff --git a/src/Checkout/PaymentSelectionKeyBuilder.php b/src/Checkout/PaymentSelectionKeyBuilder.php
new file mode 100644
index 0000000..3e1ae5f
--- /dev/null
+++ b/src/Checkout/PaymentSelectionKeyBuilder.php
@@ -0,0 +1,91 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PrestaShop\Module\PsOnePageCheckout\Checkout;
+
+class PaymentSelectionKeyBuilder
+{
+    /**
+     * @param array<int|string, mixed> $paymentOptions
+     *
+     * @return array<int|string, mixed>
+     */
+    public function enrichPaymentOptions(array $paymentOptions): array
+    {
+        foreach ($paymentOptions as $moduleName => $moduleOptions) {
+            if (!is_array($moduleOptions)) {
+                continue;
+            }
+
+            foreach ($moduleOptions as $optionIndex => $option) {
+                if (!is_array($option)) {
+                    continue;
+                }
+
+                $paymentOptions[$moduleName][$optionIndex]['selection_key'] = $this->buildSelectionKey($option);
+            }
+        }
+
+        return $paymentOptions;
+    }
+
+    /**
+     * Build a stable payment selection key from business-level option attributes.
+     * `option.id` is intentionally excluded because it is only a render identifier.
+     *
+     * @param array<string, mixed> $option
+     */
+    public function buildSelectionKey(array $option): string
+    {
+        $moduleName = (string) ($option['module_name'] ?? '');
+        $signature = [
+            'module_name' => $moduleName,
+            'action' => (string) ($option['action'] ?? ''),
+            'binary' => !empty($option['binary']),
+            'call_to_action_text' => $this->normalizeString((string) ($option['call_to_action_text'] ?? '')),
+            'inputs' => $this->normalizeInputs($option['inputs'] ?? []),
+        ];
+
+        return sprintf(
+            '%s:%s',
+            $moduleName !== '' ? $moduleName : 'unknown',
+            substr(hash('sha256', json_encode($signature)), 0, 24)
+        );
+    }
+
+    private function normalizeString(string $value): string
+    {
+        return preg_replace('/\s+/', ' ', trim($value)) ?: '';
+    }
+
+    /**
+     * @param mixed $inputs
+     *
+     * @return array<int, array<string, string>>
+     */
+    private function normalizeInputs($inputs): array
+    {
+        if (!is_array($inputs)) {
+            return [];
+        }
+
+        $normalized = [];
+        foreach ($inputs as $input) {
+            if (!is_array($input)) {
+                continue;
+            }
+
+            $normalized[] = [
+                'name' => (string) ($input['name'] ?? ''),
+                'type' => (string) ($input['type'] ?? ''),
+            ];
+        }
+
+        usort($normalized, static function (array $left, array $right): int {
+            return [$left['name'], $left['type']] <=> [$right['name'], $right['type']];
+        });
+
+        return $normalized;
+    }
+}
diff --git a/src/Form/AddressFieldsFormatTrait.php b/src/Form/AddressFieldsFormatTrait.php
index 9dd09b3..6503a5c 100644
--- a/src/Form/AddressFieldsFormatTrait.php
+++ b/src/Form/AddressFieldsFormatTrait.php
@@ -81,7 +81,7 @@ protected function getAddressFieldsFormat($prefix = '', $aliasRequired = false)
                     );
                 } elseif ($field === 'phone') {
                     $formField->setType('tel');
-                } elseif ($field === 'dni' && null !== $this->country) {
+                } elseif ($field === 'dni') {
                     if ($this->country->need_identification_number) {
                         $formField->setRequired(true);
                     }
diff --git a/src/Form/AddressFormValidationTrait.php b/src/Form/AddressFormValidationTrait.php
index 1c7b45d..905ceff 100644
--- a/src/Form/AddressFormValidationTrait.php
+++ b/src/Form/AddressFormValidationTrait.php
@@ -46,26 +46,22 @@ protected function validateAddressPostcode(
         }
 
         if ($invoicePostcode && $invoicePostcode->isRequired()) {
-            $invoiceCountry = $country;
+            $invoiceValidationCountry = $country;
             if ($invoiceCountryField && $invoiceCountryField->getValue()) {
-                $invoiceCountry = new \Country(
+                $invoiceValidationCountry = new \Country(
                     (int) $invoiceCountryField->getValue(),
                     $this->language->id
                 );
             }
-            if ($invoiceCountry) {
-                if ($invoiceCountry->need_zip_code && !$invoiceCountry->checkZipCode($invoicePostcode->getValue())) {
-                    $invoicePostcode->addError($this->translator->trans(
-                        'Invalid postcode - should look like "%zipcode%"',
-                        ['%zipcode%' => $invoiceCountry->zip_code_format],
-                        'Shop.Forms.Errors'
-                    ));
-                    $is_valid = false;
-                }
-            } elseif ($country && $country->checkZipCode($invoicePostcode->getValue()) === false) {
+
+            if (
+                $invoiceValidationCountry
+                && $invoiceValidationCountry->need_zip_code
+                && !$invoiceValidationCountry->checkZipCode($invoicePostcode->getValue())
+            ) {
                 $invoicePostcode->addError($this->translator->trans(
                     'Invalid postcode - should look like "%zipcode%"',
-                    ['%zipcode%' => $country->zip_code_format],
+                    ['%zipcode%' => $invoiceValidationCountry->zip_code_format],
                     'Shop.Forms.Errors'
                 ));
                 $is_valid = false;
diff --git a/src/Form/BackOfficeConfigurationForm.php b/src/Form/BackOfficeConfigurationForm.php
index fc0a48c..d623aec 100644
--- a/src/Form/BackOfficeConfigurationForm.php
+++ b/src/Form/BackOfficeConfigurationForm.php
@@ -50,6 +50,12 @@ public function renderBackOfficeConfiguration(): string
         $output = '';
 
         if (\Tools::isSubmit(self::FORM_SUBMIT_ACTION)) {
+            if (!$this->isSingleShopContext()) {
+                $this->redirectToConfigurationForm();
+
+                return '';
+            }
+
             $isEnabled = (int) \Tools::getValue($this->configurationKey, 0) === 1;
             $this->persistConfigurationValue((int) $isEnabled);
             $this->storeSuccessFlash();
diff --git a/src/Form/OnePageCheckoutAddressForm.php b/src/Form/OnePageCheckoutAddressForm.php
new file mode 100644
index 0000000..0d501d7
--- /dev/null
+++ b/src/Form/OnePageCheckoutAddressForm.php
@@ -0,0 +1,156 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Form;
+
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class OnePageCheckoutAddressForm extends \AbstractForm
+{
+    use AddressFormValidationTrait;
+
+    /**
+     * @var OnePageCheckoutAddressFormatter
+     */
+    protected $formatter;
+
+    private \Language $language;
+
+    public function __construct(
+        \Smarty $smarty,
+        \Language $language,
+        TranslatorInterface $translator,
+        OnePageCheckoutAddressFormatter $formatter,
+    ) {
+        parent::__construct(
+            $smarty,
+            $translator,
+            $formatter
+        );
+
+        $this->language = $language;
+        $this->formatter = $formatter;
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     */
+    public function fillFromRequest(array $requestParameters, string $prefix = ''): self
+    {
+        $this->syncFormatterCountryFromRequest($requestParameters, $prefix);
+
+        $params = [];
+        foreach ($this->getAllowedFieldNames() as $fieldName) {
+            $params[$fieldName] = $requestParameters[$prefix . $fieldName] ?? $requestParameters[$fieldName] ?? null;
+        }
+
+        return $this->fillWith($params);
+    }
+
+    public function fillWith(array $params = [])
+    {
+        if (isset($params['id_country']) && (int) $params['id_country'] > 0) {
+            $country = (int) $params['id_country'] !== (int) $this->formatter->getCountry()->id
+                ? new \Country((int) $params['id_country'], (int) $this->language->id)
+                : $this->formatter->getCountry();
+
+            $this->formatter->setCountry($country);
+        }
+
+        return parent::fillWith($params);
+    }
+
+    /**
+     * @param array<string,mixed> $requestParameters
+     */
+    private function syncFormatterCountryFromRequest(array $requestParameters, string $prefix): void
+    {
+        $requestedCountryId = (int) ($requestParameters[$prefix . 'id_country'] ?? $requestParameters['id_country'] ?? 0);
+        if ($requestedCountryId <= 0) {
+            return;
+        }
+
+        if ((int) $this->formatter->getCountry()->id !== $requestedCountryId) {
+            $this->formatter->setCountry(new \Country($requestedCountryId, (int) $this->language->id));
+        }
+
+        // Rebuild the allowed fields from the requested country before extracting request values.
+        $this->formFields = [];
+    }
+
+    public function validate()
+    {
+        $country = $this->formatter->getCountry();
+        $isValid = $this->validateAddressPostcode(
+            $this->getField('postcode'),
+            $country
+        );
+
+        if ($isValid) {
+            $isValid = $this->validateAddressFormHook();
+        }
+
+        return $isValid && parent::validate();
+    }
+
+    /**
+     * @return \Address|false
+     */
+    public function submit()
+    {
+        if (!$this->validate()) {
+            return false;
+        }
+
+        return $this->buildAddress();
+    }
+
+    public function buildAddress(?\Address $address = null): \Address
+    {
+        $address = $address ?? new \Address(null, (int) $this->language->id);
+
+        foreach ($this->formFields as $field) {
+            $fieldName = $field->getName();
+            if (property_exists($address, $fieldName)) {
+                $address->{$fieldName} = $field->getValue();
+            }
+        }
+
+        if (!$this->getField('id_state')) {
+            $address->id_state = 0;
+        }
+
+        return $address;
+    }
+
+    /**
+     * @return list<string>
+     */
+    public function getAllowedFieldNames(): array
+    {
+        if (!$this->formFields) {
+            $this->formFields = $this->formatter->getFormat();
+        }
+
+        return array_keys($this->formFields);
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    public function getTemplateVariables()
+    {
+        if (!$this->formFields) {
+            $this->formFields = $this->formatter->getFormat();
+        }
+
+        return [
+            'errors' => $this->getErrors(),
+            'formFields' => array_map(
+                static function (\FormField $field): array {
+                    return $field->toArray();
+                },
+                $this->formFields
+            ),
+        ];
+    }
+}
diff --git a/src/Form/OnePageCheckoutAddressFormatter.php b/src/Form/OnePageCheckoutAddressFormatter.php
new file mode 100644
index 0000000..69803dc
--- /dev/null
+++ b/src/Form/OnePageCheckoutAddressFormatter.php
@@ -0,0 +1,81 @@
+<?php
+
+namespace PrestaShop\Module\PsOnePageCheckout\Form;
+
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class OnePageCheckoutAddressFormatter implements \FormFormatterInterface
+{
+    use AddressFieldsFormatTrait;
+
+    protected \Country $country;
+    protected TranslatorInterface $translator;
+
+    /**
+     * @var array<int, mixed>
+     */
+    protected array $availableCountries;
+
+    /**
+     * @var array<string, mixed>
+     */
+    protected array $definition;
+
+    /**
+     * @param array<int, mixed> $availableCountries
+     */
+    public function __construct(
+        \Country $country,
+        TranslatorInterface $translator,
+        array $availableCountries,
+    ) {
+        $this->country = $country;
+        $this->translator = $translator;
+        $this->availableCountries = $availableCountries;
+        $this->definition = \Address::$definition['fields'];
+    }
+
+    public function setCountry(\Country $country): self
+    {
+        $this->country = $country;
+
+        return $this;
+    }
+
+    public function getCountry(): \Country
+    {
+        return $this->country;
+    }
+
+    /**
+     * @return array<string,\FormField>
+     */
+    public function getFormat(): array
+    {
+        $format = $this->addConstraints(
+            $this->addMaxLength(
+                $this->getAddressFieldsFormat('', false)
+            )
+        );
+
+        $additionalAddressFormFields = \Hook::exec('additionalCustomerAddressFields', ['fields' => &$format], null, true);
+        if (is_array($additionalAddressFormFields)) {
+            foreach ($additionalAddressFormFields as $moduleName => $additionalFormFields) {
+                if (!is_array($additionalFormFields)) {
+                    continue;
+                }
+
+                foreach ($additionalFormFields as $formField) {
+                    if (!$formField instanceof \FormField) {
+                        continue;
+                    }
+
+                    $formField->moduleName = $moduleName;
+                    $format[$moduleName . '_' . $formField->getName()] = $formField;
+                }
+            }
+        }
+
+        return $format;
+    }
+}
diff --git a/src/Form/OnePageCheckoutForm.php b/src/Form/OnePageCheckoutForm.php
index de636c7..bf7c290 100644
--- a/src/Form/OnePageCheckoutForm.php
+++ b/src/Form/OnePageCheckoutForm.php
@@ -29,9 +29,10 @@
 
 use Address;
 use Cart;
-use Context;
 use Country;
 use Customer;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerContextResolver;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerTemplateBuilder;
 use PrestaShop\PrestaShop\Core\Util\InternationalizedDomainNameConverter;
 use Symfony\Contracts\Translation\TranslatorInterface;
 use Validate;
@@ -40,7 +41,6 @@ class OnePageCheckoutForm extends \AbstractForm
 {
     use AddressFormValidationTrait;
 
-    protected $template = 'checkout/_partials/one-page-checkout-form.tpl';
     private const GUEST_PLACEHOLDER_FIRSTNAME = 'Guest';
     private const GUEST_PLACEHOLDER_LASTNAME = 'Guest';
 
@@ -115,7 +115,12 @@ public function fillWith(array $params = [])
             $this->formatter->setInvoiceCountry($invoiceCountry);
         }
 
-        return parent::fillWith($params);
+        parent::fillWith($params);
+
+        $this->stripAdditionalCustomerFieldsForConnectedCustomer();
+        $this->hydrateConnectedCustomerEmail();
+
+        return $this;
     }
 
     public function fillFromCustomer(\Customer $customer)
@@ -139,7 +144,7 @@ public function fillFromAddress(\Address $address)
     {
         $this->address = $address;
         $params = get_object_vars($address);
-        $params['id_address'] = $address->id;
+        $params['id_address_delivery'] = $address->id;
 
         return $this->fillWith($params);
     }
@@ -161,7 +166,7 @@ public function fillFromAddresses(?\Address $deliveryAddress = null, ?\Address $
                     $params[$key] = $value;
                 }
             }
-            $params['id_address'] = $deliveryAddress->id;
+            $params['id_address_delivery'] = $deliveryAddress->id;
         }
         $deliveryAddressId = $deliveryAddress ? $deliveryAddress->id : 0;
 
@@ -180,6 +185,31 @@ public function fillFromAddresses(?\Address $deliveryAddress = null, ?\Address $
         return $this->fillWith($params);
     }
 
+    /**
+     * Restore the last failed submit state after the AJAX submit redirects back to /order.
+     *
+     * @param array<string,mixed> $params
+     * @param array<string,mixed> $errors
+     */
+    public function restoreSubmissionState(array $params, array $errors): self
+    {
+        $this->fillWith($params);
+        $this->errors = ['' => is_array($errors[''] ?? null) ? $errors[''] : []];
+
+        foreach ($errors as $fieldName => $fieldErrors) {
+            if ($fieldName === '' || !is_array($fieldErrors)) {
+                continue;
+            }
+
+            $field = $this->getField((string) $fieldName);
+            if ($field) {
+                $field->setErrors($fieldErrors);
+            }
+        }
+
+        return $this;
+    }
+
     public function validate()
     {
         // When use_same_address, invoice fields are optional (skipped)
@@ -210,6 +240,10 @@ public function validate()
             $is_valid = $this->validateAddressFormHook();
         }
 
+        if ($is_valid) {
+            $this->validateCustomerFieldsByModules();
+        }
+
         return $is_valid && parent::validate();
     }
 
@@ -224,13 +258,11 @@ public function submit()
             return false;
         }
 
-        $this->syncContextCustomerFromCart();
-
-        // Get customer from form data
-        $customer = $this->getCustomer();
+        $fieldsByGroup = $this->mapFieldsByGroup();
+        $customer = $this->getCheckoutCustomerForSubmit($fieldsByGroup);
 
-        // If customer is not logged in, create/update guest customer
-        if (!$this->context->customer->isLogged() || $this->context->customer->isGuest()) {
+        if ((int) $customer->id <= 0 || $customer->isGuest()) {
+            $customer = $this->buildCustomerFromFields($this->getCustomerFields($fieldsByGroup));
             $customer->is_guest = true;
 
             if (!$this->customerPersister->save($customer, '', '', false)) {
@@ -247,38 +279,63 @@ public function submit()
             $this->context->updateCustomer($customer);
         }
 
+        $this->refreshAddressPersister();
+
         $token = \Tools::getToken(true, $this->context);
         $useSameAddress = $this->getField('use_same_address') && $this->getField('use_same_address')->getValue();
 
-        // Create/update delivery address
-        $deliveryAddress = $this->buildAddressFromFields('', \Tools::getValue('id_address'));
-        $deliveryAddress->id_customer = $customer->id;
-        if (empty($deliveryAddress->alias)) {
-            $deliveryAddress->alias = $this->translator->trans('My Address', [], 'Shop.Theme.Checkout');
-        }
-        \Hook::exec('actionSubmitCustomerAddressForm', ['address' => &$deliveryAddress]);
-        if (!$this->addressPersister->save($deliveryAddress, $token)) {
-            return false;
+        $deliveryAddress = $this->resolveSelectedCustomerAddress(
+            $this->resolveSelectedDeliveryAddressId(),
+            (int) $customer->id
+        );
+
+        if ($deliveryAddress instanceof \Address) {
+            $idAddressDelivery = (int) $deliveryAddress->id;
+        } else {
+            $deliveryAddress = $this->buildAddressFromGroup(
+                $fieldsByGroup['deliveryFields'],
+                null
+            );
+            $deliveryAddress->id_customer = $customer->id;
+            if (empty($deliveryAddress->alias)) {
+                $deliveryAddress->alias = $this->translator->trans('My Address', [], 'Shop.Theme.Checkout');
+            }
+            \Hook::exec('actionSubmitCustomerAddressForm', ['address' => &$deliveryAddress]);
+            if (!$this->addressPersister->save($deliveryAddress, $token)) {
+                return false;
+            }
+
+            $idAddressDelivery = (int) $deliveryAddress->id;
         }
 
-        $idAddressDelivery = $deliveryAddress->id;
         $idAddressInvoice = $idAddressDelivery;
 
         // Create/update invoice address if different
         if (!$useSameAddress) {
             $idAddressInvoice = (int) \Tools::getValue('id_address_invoice');
-            $invoiceAddress = $this->buildAddressFromFields('invoice_', $idAddressInvoice ?: null);
-            $invoiceAddress->id_customer = $customer->id;
-            $invoiceAddress->alias = $invoiceAddress->alias ?: $this->translator->trans(
-                'Invoice address',
-                [],
-                'Shop.Theme.Checkout'
-            );
-            \Hook::exec('actionSubmitCustomerAddressForm', ['address' => &$invoiceAddress]);
-            if (!$this->addressPersister->save($invoiceAddress, $token)) {
-                return false;
+            $invoiceAddress = $this->resolveSelectedCustomerAddress($idAddressInvoice, (int) $customer->id);
+
+            if ($invoiceAddress instanceof \Address) {
+                $idAddressInvoice = (int) $invoiceAddress->id;
+            } else {
+                $invoiceAddress = $this->buildAddressFromGroup(
+                    $fieldsByGroup['invoiceFields'],
+                    null,
+                    'invoice_'
+                );
+                $invoiceAddress->id_customer = $customer->id;
+                $invoiceAddress->alias = $invoiceAddress->alias ?: $this->translator->trans(
+                    'Invoice address',
+                    [],
+                    'Shop.Theme.Checkout'
+                );
+                \Hook::exec('actionSubmitCustomerAddressForm', ['address' => &$invoiceAddress]);
+                if (!$this->addressPersister->save($invoiceAddress, $token)) {
+                    return false;
+                }
+
+                $idAddressInvoice = (int) $invoiceAddress->id;
             }
-            $idAddressInvoice = $invoiceAddress->id;
         }
 
         return [
@@ -288,38 +345,85 @@ public function submit()
     }
 
     /**
-     * In OPC, guest auto-save can attach a guest to the cart just before final submit.
-     * If `context->customer` is still empty, final submit may create a duplicate guest.
-     * Reload persisted cart owner and sync context only when that owner is a guest.
+     * Final submit must follow the cart owner stored in persistence, not the current session flags.
+     * When a registered customer already owns the cart, we keep that customer as checkout owner.
+     *
+     * @param array<string, array<string, \FormField>> $fieldsByGroup
      */
-    private function syncContextCustomerFromCart(): void
+    private function getCheckoutCustomerForSubmit(array $fieldsByGroup): \Customer
+    {
+        $persistedCartOwner = $this->getPersistedCartOwner();
+        if ($persistedCartOwner && !$persistedCartOwner->isGuest()) {
+            $this->context->updateCustomer($persistedCartOwner);
+
+            return $persistedCartOwner;
+        }
+
+        $this->syncContextCustomerFromCart();
+
+        return $this->buildCustomerFromFields($this->getCustomerFields($fieldsByGroup));
+    }
+
+    private function refreshAddressPersister(): void
     {
-        if ((int) $this->context->customer->id > 0 || !\Validate::isLoadedObject($this->context->cart)) {
+        if (get_class($this->addressPersister) !== \CustomerAddressPersister::class) {
             return;
         }
 
-        $cartId = (int) $this->context->cart->id;
-        if ($cartId <= 0) {
+        $this->addressPersister = new \CustomerAddressPersister(
+            $this->context->customer,
+            $this->context->cart,
+            \Tools::getToken(true, $this->context)
+        );
+    }
+
+    private function syncContextCustomerFromCart(): void
+    {
+        if (!isset($this->context->cart) || !\Validate::isUnsignedId((int) $this->context->cart->id)) {
             return;
         }
 
-        // Read cart owner from DB to align final submit with the real cart owner.
-        $freshCart = new \Cart($cartId);
+        $freshCart = new \Cart((int) $this->context->cart->id);
         if (!\Validate::isLoadedObject($freshCart)) {
             return;
         }
 
-        $cartCustomerId = (int) $freshCart->id_customer;
-        if ($cartCustomerId <= 0) {
+        $cartCustomer = $this->getPersistedCartOwner();
+        if (!$cartCustomer) {
             return;
         }
 
-        $cartCustomer = new \Customer($cartCustomerId);
-        if (!\Validate::isLoadedObject($cartCustomer) || !$cartCustomer->isGuest()) {
+        if (
+            !\Validate::isLoadedObject($this->context->cart)
+            || (int) $this->context->cart->id_customer !== (int) $freshCart->id_customer
+            || (int) $this->context->cart->id_currency <= 0
+            || (int) $this->context->cart->id_lang <= 0
+            || (int) $this->context->cart->id_shop <= 0
+        ) {
+            $this->context->cart = $freshCart;
+        }
+
+        if ((int) $this->context->customer->id === (int) $cartCustomer->id) {
             return;
         }
 
-        $this->context->customer = $cartCustomer;
+        $this->context->updateCustomer($cartCustomer);
+    }
+
+    private function getPersistedCartOwner(): ?\Customer
+    {
+        if (!isset($this->context->cart) || !\Validate::isUnsignedId((int) $this->context->cart->id)) {
+            return null;
+        }
+
+        $freshCart = new \Cart((int) $this->context->cart->id);
+        if (!\Validate::isLoadedObject($freshCart) || (int) $freshCart->id_customer <= 0) {
+            return null;
+        }
+
+        $cartCustomer = new \Customer((int) $freshCart->id_customer);
+
+        return \Validate::isLoadedObject($cartCustomer) ? $cartCustomer : null;
     }
 
     /**
@@ -330,12 +434,13 @@ private function syncContextCustomerFromCart(): void
     public function submitGuestInit(array $params = []): bool
     {
         $this->fillWith($params);
+        $fieldsByGroup = $this->mapFieldsByGroup();
 
-        if (!$this->validateGuestInit()) {
+        if (!$this->validateGuestInit($fieldsByGroup)) {
             return false;
         }
 
-        $customer = $this->getCustomer();
+        $customer = $this->buildCustomerFromFields($this->getCustomerFields($fieldsByGroup));
         $customer->is_guest = true;
         $customer->firstname = $customer->firstname ?: self::GUEST_PLACEHOLDER_FIRSTNAME;
         $customer->lastname = $customer->lastname ?: self::GUEST_PLACEHOLDER_LASTNAME;
@@ -348,48 +453,65 @@ public function submitGuestInit(array $params = []): bool
     }
 
     /**
-     * Build Address object from form fields with given prefix
-     *
-     * @param string $prefix Field prefix ('' for delivery, 'invoice_' for invoice)
-     * @param int|null $idAddress Existing address ID or null for new
-     *
-     * @return \Address
+     * @param array<string, array<string, \FormField>> $fieldsByGroup
      */
-    private function buildAddressFromFields($prefix, $idAddress)
+    private function validateGuestInit(array $fieldsByGroup): bool
     {
-        $address = new \Address($idAddress ? (int) $idAddress : null, $this->language->id);
-
-        foreach ($this->formFields as $formField) {
-            $fieldName = $formField->getName();
-            if (strpos($fieldName, $prefix) !== 0) {
-                continue;
-            }
-            $baseName = $prefix ? substr($fieldName, strlen($prefix)) : $fieldName;
-            if (property_exists($address, $baseName)) {
-                $address->{$baseName} = $formField->getValue();
-            }
+        if (!$this->isGuestInitEmailValid()) {
+            return false;
         }
 
-        if (!isset($this->formFields[$prefix . 'id_state'])) {
-            $address->id_state = 0;
+        if (!$this->formFields) {
+            $this->formFields = $this->formatter->getFormat();
+            $this->stripAdditionalCustomerFieldsForConnectedCustomer();
         }
 
-        return $address;
+        $this->validateRequiredGuestConsentFields($fieldsByGroup);
+
+        return !$this->hasErrors();
     }
 
-    private function validateGuestInit(): bool
+    protected function validateCustomerFieldsByModules(): void
     {
-        if (!$this->isGuestInitEmailValid()) {
-            return false;
-        }
+        $formFieldsAssociated = [];
+        $formFieldKeysByModule = [];
+        $additionalCustomerFields = $this->mapFieldsByGroup()['additionalCustomerFields'];
 
-        if (!$this->formFields) {
-            $this->formFields = $this->formatter->getFormat();
+        foreach ($additionalCustomerFields as $key => $formField) {
+            if (empty($formField->moduleName)) {
+                continue;
+            }
+
+            $formFieldsAssociated[$formField->moduleName][] = $formField;
+            $formFieldKeysByModule[$formField->moduleName][$formField->getName()] = $key;
         }
 
-        $this->validateRequiredGuestConsentFields();
+        foreach ($formFieldsAssociated as $moduleName => $formFields) {
+            $moduleId = \Module::getModuleIdByName($moduleName);
+            if (!$moduleId) {
+                continue;
+            }
 
-        return !$this->hasErrors();
+            $validatedCustomerFormFields = \Hook::exec(
+                'validateCustomerFormFields',
+                ['fields' => $formFields],
+                $moduleId,
+                true
+            );
+
+            if (!is_array($validatedCustomerFormFields)) {
+                continue;
+            }
+
+            foreach ($validatedCustomerFormFields as $name => $field) {
+                if (!$field instanceof \FormFieldCore) {
+                    continue;
+                }
+
+                $targetKey = $formFieldKeysByModule[$moduleName][$name] ?? $name;
+                $this->formFields[$targetKey] = $field;
+            }
+        }
     }
 
     /**
@@ -447,10 +569,14 @@ private function isGuestInitEmailValid(): bool
      *
      * @return void
      */
-    private function validateRequiredGuestConsentFields(): void
+    /**
+     * @param array<string, array<string, \FormField>> $fieldsByGroup
+     */
+    private function validateRequiredGuestConsentFields(array $fieldsByGroup): void
     {
-        foreach ($this->formFields as $field) {
-            if ($field->getType() !== 'checkbox' || !$field->isRequired()) {
+        $guestFields = $fieldsByGroup['contactFields'] + $fieldsByGroup['additionalCustomerFields'];
+        foreach ($guestFields as $field) {
+            if (!in_array($field->getType(), ['checkbox', 'radio-buttons'], true) || !$field->isRequired()) {
                 continue;
             }
 
@@ -467,16 +593,9 @@ private function validateRequiredGuestConsentFields(): void
      */
     public function getCustomer()
     {
-        $customer = new \Customer($this->context->customer->id);
-
-        foreach ($this->formFields as $field) {
-            $customerField = $field->getName();
-            if (property_exists($customer, $customerField)) {
-                $customer->$customerField = $field->getValue();
-            }
-        }
-
-        return $customer;
+        return $this->buildCustomerFromFields(
+            $this->getCustomerFields($this->mapFieldsByGroup())
+        );
     }
 
     /**
@@ -486,7 +605,9 @@ public function getCustomer()
      */
     public function getAddress()
     {
-        return $this->buildAddressFromFields('', \Tools::getValue('id_address'));
+        $fieldsByGroup = $this->mapFieldsByGroup();
+
+        return $this->buildAddressFromGroup($fieldsByGroup['deliveryFields'], $this->resolveSelectedDeliveryAddressId());
     }
 
     /**
@@ -496,28 +617,269 @@ public function getAddress()
      */
     public function getInvoiceAddress()
     {
-        return $this->buildAddressFromFields('invoice_', null);
+        $fieldsByGroup = $this->mapFieldsByGroup();
+
+        return $this->buildAddressFromGroup($fieldsByGroup['invoiceFields'], null, 'invoice_');
     }
 
     public function getTemplateVariables()
     {
         if (!$this->formFields) {
-            // This is usually done by fillWith but the form may be
-            // rendered before fillWith is called.
             $this->formFields = $this->formatter->getFormat();
+            $this->stripAdditionalCustomerFieldsForConnectedCustomer();
         }
 
-        $formFields = array_map(
-            function (\FormField $item) {
-                return $item->toArray();
-            },
-            $this->formFields
-        );
+        $fieldsByGroup = $this->mapFieldsByGroup();
+        $formFields = $this->convertFieldsToTemplateArray($this->formFields);
 
         return [
             'action' => $this->action,
             'errors' => $this->getErrors(),
+            'customer' => $this->buildCheckoutCustomerTemplateVariables(),
             'formFields' => $formFields,
+            'contactFields' => $this->convertFieldsToTemplateArray($fieldsByGroup['contactFields']),
+            'additionalCustomerFields' => $this->convertFieldsToTemplateArray($fieldsByGroup['additionalCustomerFields']),
+            'useSameAddressField' => $this->convertFieldToTemplateArray($fieldsByGroup['useSameAddressField']['use_same_address'] ?? null),
+            'deliveryFields' => $this->convertFieldsToTemplateArray($fieldsByGroup['deliveryFields']),
+            'invoiceFields' => $this->convertFieldsToTemplateArray($fieldsByGroup['invoiceFields']),
+            'invoiceMetaFields' => $this->convertFieldsToTemplateArray($fieldsByGroup['invoiceMetaFields']),
+            'token' => \Tools::getToken(true, $this->context),
+        ];
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    private function buildCheckoutCustomerTemplateVariables(): array
+    {
+        return (new CheckoutCustomerTemplateBuilder(
+            $this->context,
+            new CheckoutCustomerContextResolver($this->context)
+        ))->build();
+    }
+
+    private function resolveSelectedDeliveryAddressId(): ?int
+    {
+        $selectedDeliveryAddressId = (int) \Tools::getValue('id_address_delivery');
+
+        return $selectedDeliveryAddressId > 0 ? $selectedDeliveryAddressId : null;
+    }
+
+    private function resolveSelectedCustomerAddress(?int $addressId, int $customerId): ?\Address
+    {
+        if ($addressId === null || $addressId <= 0 || $customerId <= 0) {
+            return null;
+        }
+
+        $address = new \Address($addressId, (int) $this->language->id);
+
+        if (!\Validate::isLoadedObject($address) || (int) $address->id_customer !== $customerId) {
+            return null;
+        }
+
+        return $address;
+    }
+
+    /**
+     * @return array<string, array<string, \FormField>>
+     */
+    private function mapFieldsByGroup(): array
+    {
+        $fieldsByGroup = [
+            'contactFields' => [],
+            'additionalCustomerFields' => [],
+            'useSameAddressField' => [],
+            'deliveryFields' => [],
+            'invoiceFields' => [],
+            'invoiceMetaFields' => [],
         ];
+
+        foreach ($this->formFields as $key => $field) {
+            if ($this->isCustomerField($key, $field)) {
+                $fieldsByGroup['additionalCustomerFields'][$key] = $field;
+                continue;
+            }
+
+            if ($this->isContactField($key)) {
+                $fieldsByGroup['contactFields'][$key] = $field;
+                continue;
+            }
+
+            if ($this->isUseSameAddressField($key)) {
+                $fieldsByGroup['useSameAddressField'][$key] = $field;
+                continue;
+            }
+
+            if ($this->isInvoiceMetaField($key)) {
+                $fieldsByGroup['invoiceMetaFields'][$key] = $field;
+                continue;
+            }
+
+            if ($this->isInvoiceField($key)) {
+                $fieldsByGroup['invoiceFields'][$key] = $field;
+                continue;
+            }
+
+            $fieldsByGroup['deliveryFields'][$key] = $field;
+        }
+
+        return $fieldsByGroup;
+    }
+
+    private function stripAdditionalCustomerFieldsForConnectedCustomer(): void
+    {
+        if (!$this->isRegisteredCustomer()) {
+            return;
+        }
+
+        foreach ($this->formFields as $key => $field) {
+            if ($this->isCustomerField($key, $field)) {
+                unset($this->formFields[$key]);
+            }
+        }
+    }
+
+    private function isRegisteredCustomer(): bool
+    {
+        $customer = $this->context->customer;
+
+        return $customer instanceof \Customer
+            && !empty($customer->id)
+            && !$customer->isGuest();
+    }
+
+    private function hydrateConnectedCustomerEmail(): void
+    {
+        if (!$this->isRegisteredCustomer()) {
+            return;
+        }
+
+        $emailField = $this->getField('email');
+        if (!$emailField || $emailField->getValue()) {
+            return;
+        }
+
+        $email = (string) $this->context->customer->email;
+        if (!\Validate::isEmail($email)) {
+            return;
+        }
+
+        $emailField->setValue($email);
+    }
+
+    private function isCustomerField(string $key, ?\FormField $field = null): bool
+    {
+        if ($this->formatter->getFieldGroup($key) === 'customer') {
+            return true;
+        }
+
+        if (strpos($key, 'customer_') === 0) {
+            return true;
+        }
+
+        if ($field && strpos((string) $field->getName(), '_customer_') !== false) {
+            return true;
+        }
+
+        return false;
+    }
+
+    private function isContactField(string $key): bool
+    {
+        return in_array($key, ['email', 'optin'], true);
+    }
+
+    private function isUseSameAddressField(string $key): bool
+    {
+        return $key === 'use_same_address';
+    }
+
+    private function isInvoiceMetaField(string $key): bool
+    {
+        return $key === 'id_address_invoice';
+    }
+
+    private function isInvoiceField(string $key): bool
+    {
+        return strpos($key, 'invoice_') === 0;
+    }
+
+    /**
+     * @param array<string, array<string, \FormField>> $fieldsByGroup
+     *
+     * @return array<string, \FormField>
+     */
+    private function getCustomerFields(array $fieldsByGroup): array
+    {
+        return $fieldsByGroup['contactFields']
+            + $fieldsByGroup['additionalCustomerFields']
+            + $fieldsByGroup['deliveryFields'];
+    }
+
+    /**
+     * @param array<string, \FormField> $fields
+     */
+    private function buildCustomerFromFields(array $fields): \Customer
+    {
+        $customerId = (int) $this->context->customer->id;
+        $customer = $customerId > 0 ? new \Customer($customerId) : new \Customer();
+
+        foreach ($fields as $field) {
+            $customerField = $field->getName();
+            if (property_exists($customer, $customerField)) {
+                $customer->$customerField = $field->getValue();
+            }
+        }
+
+        return $customer;
+    }
+
+    /**
+     * @param array<string, \FormField> $fields
+     * @param int|null $idAddress
+     */
+    private function buildAddressFromGroup(array $fields, $idAddress, string $prefix = ''): \Address
+    {
+        $address = new \Address($idAddress ? (int) $idAddress : null, $this->language->id);
+
+        foreach ($fields as $formField) {
+            $fieldName = $formField->getName();
+            $baseName = $prefix && strpos($fieldName, $prefix) === 0
+                ? substr($fieldName, strlen($prefix))
+                : $fieldName;
+
+            if (property_exists($address, $baseName)) {
+                $address->{$baseName} = $formField->getValue();
+            }
+        }
+
+        if (!isset($fields[$prefix . 'id_state'])) {
+            $address->id_state = 0;
+        }
+
+        return $address;
+    }
+
+    /**
+     * @param array<string, \FormField> $fields
+     *
+     * @return array<string, array<string, mixed>>
+     */
+    private function convertFieldsToTemplateArray(array $fields): array
+    {
+        return array_map(
+            function (\FormField $field) {
+                return $field->toArray();
+            },
+            $fields
+        );
+    }
+
+    /**
+     * @return array<string, mixed>|null
+     */
+    private function convertFieldToTemplateArray(?\FormField $field): ?array
+    {
+        return $field ? $field->toArray() : null;
     }
 }
diff --git a/src/Form/OnePageCheckoutFormFactory.php b/src/Form/OnePageCheckoutFormFactory.php
index cdcffba..ecf8a04 100644
--- a/src/Form/OnePageCheckoutFormFactory.php
+++ b/src/Form/OnePageCheckoutFormFactory.php
@@ -118,4 +118,14 @@ public function createAddressPersister(): \CustomerAddressPersister
             \Tools::getToken(true, $this->context)
         );
     }
+
+    public function createCustomerAddressFormatter(): OnePageCheckoutFormatter
+    {
+        return $this->createFormatter($this->getAvailableCountries());
+    }
+
+    public function createCustomerAddressForm(): OnePageCheckoutForm
+    {
+        return $this->create();
+    }
 }
diff --git a/src/Form/OnePageCheckoutFormatter.php b/src/Form/OnePageCheckoutFormatter.php
index 0cb5255..38c33b2 100644
--- a/src/Form/OnePageCheckoutFormatter.php
+++ b/src/Form/OnePageCheckoutFormatter.php
@@ -35,10 +35,17 @@ class OnePageCheckoutFormatter implements \FormFormatterInterface
 {
     use AddressFieldsFormatTrait;
 
+    public const FIELD_GROUP_CUSTOMER = 'customer';
+    public const FIELD_GROUP_ADDRESS = 'address';
+
     protected $country;
     protected $translator;
     protected $availableCountries;
     protected $definition;
+    /**
+     * @var array<string, string>
+     */
+    private array $fieldGroups = [];
 
     /**
      * Separate country for the billing (invoice) address section.
@@ -88,6 +95,7 @@ public function setInvoiceCountry(\Country $country)
     public function getFormat()
     {
         $format = [];
+        $this->fieldGroups = [];
 
         // Identity section: email only
         $format['email'] = (new \FormField())
@@ -130,8 +138,10 @@ public function getFormat()
                         continue;
                     }
 
+                    $fieldKey = $moduleName . '_' . $formField->getName();
                     $formField->moduleName = $moduleName;
-                    $format[$moduleName . '_' . $formField->getName()] = $formField;
+                    $this->fieldGroups[$fieldKey] = self::FIELD_GROUP_CUSTOMER;
+                    $format[$fieldKey] = $formField;
                 }
             }
         }
@@ -149,24 +159,31 @@ public function getFormat()
             )
             ->setValue(true);
 
+        // Hidden field to preserve delivery address ID when editing
+        $format['id_address_delivery'] = (new \FormField())
+            ->setName('id_address_delivery')
+            ->setType('hidden');
+
         // Hidden field to preserve invoice address ID when editing
         $format['id_address_invoice'] = (new \FormField())
             ->setName('id_address_invoice')
             ->setType('hidden');
 
         // Delivery address fields
-        $format = array_merge($format, $this->getAddressFieldsFormat('', true));
+        $format = array_merge($format, $this->getAddressFieldsFormat('', false));
 
         // Invoice address fields (prefixed with invoice_)
         if ($this->invoiceCountry !== null) {
             $deliveryCountry = $this->getCountry();
             $this->setCountry($this->invoiceCountry);
-            $format = array_merge($format, $this->getAddressFieldsFormat('invoice_', true));
+            $format = array_merge($format, $this->getAddressFieldsFormat('invoice_', false));
             $this->setCountry($deliveryCountry);
         } else {
-            $format = array_merge($format, $this->getAddressFieldsFormat('invoice_', true));
+            $format = array_merge($format, $this->getAddressFieldsFormat('invoice_', false));
         }
 
+        $format = $this->sortAddressFields($format);
+
         // Add constraints and max length
         $format = $this->addConstraints(
             $this->addMaxLength($format)
@@ -184,8 +201,10 @@ public function getFormat()
                         continue;
                     }
 
+                    $fieldKey = $moduleName . '_' . $formField->getName();
                     $formField->moduleName = $moduleName;
-                    $format[$moduleName . '_' . $formField->getName()] = $formField;
+                    $this->fieldGroups[$fieldKey] = self::FIELD_GROUP_ADDRESS;
+                    $format[$fieldKey] = $formField;
                 }
             }
         }
@@ -204,4 +223,44 @@ protected function getDefinitionKey($name)
     {
         return strpos($name, 'invoice_') === 0 ? substr($name, 8) : $name;
     }
+
+    /**
+     * @param array<string, \FormField> $fields
+     *
+     * @return array<string, \FormField>
+     */
+    protected function sortAddressFields(array $fields): array
+    {
+        $customOrder = [
+            'id_country' => 1,
+            'alias' => 2,
+            'firstname' => 3,
+            'lastname' => 4,
+            'company' => 5,
+            'vat_number' => 6,
+            'address1' => 7,
+            'address2' => 8,
+            'city' => 9,
+            'postcode' => 10,
+            'id_state' => 11,
+            'phone' => 12,
+        ];
+
+        uksort($fields, static function (string $keyA, string $keyB) use ($customOrder): int {
+            $baseA = str_replace('invoice_', '', $keyA);
+            $baseB = str_replace('invoice_', '', $keyB);
+
+            $positionA = $customOrder[$baseA] ?? 999;
+            $positionB = $customOrder[$baseB] ?? 999;
+
+            return $positionA <=> $positionB;
+        });
+
+        return $fields;
+    }
+
+    public function getFieldGroup(string $key): ?string
+    {
+        return $this->fieldGroups[$key] ?? null;
+    }
 }
diff --git a/tests/php/Fixtures/CheckoutTestFixtures.php b/tests/php/Fixtures/CheckoutTestFixtures.php
new file mode 100644
index 0000000..60011e6
--- /dev/null
+++ b/tests/php/Fixtures/CheckoutTestFixtures.php
@@ -0,0 +1,232 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Fixtures;
+
+final class CheckoutTestFixtures
+{
+    public static function context(array $overrides = []): \Context
+    {
+        $context = new ContextStub();
+
+        foreach ($overrides as $property => $value) {
+            $context->{$property} = $value;
+        }
+
+        return $context;
+    }
+
+    public static function language(int $id = 1): \Language
+    {
+        $language = new LanguageStub();
+        $language->id = $id;
+
+        return $language;
+    }
+
+    /**
+     * @param array<string, mixed> $overrides
+     */
+    public static function country(array $overrides = []): \Country
+    {
+        $country = new CountryStub();
+
+        foreach ($overrides as $property => $value) {
+            $country->{$property} = $value;
+        }
+
+        return $country;
+    }
+
+    /**
+     * @param array<int, array<string, mixed>> $simpleAddresses
+     * @param array<string, mixed> $overrides
+     */
+    public static function customer(
+        array $simpleAddresses = [],
+        bool $logged = false,
+        bool $guest = false,
+        array $overrides = [],
+    ): \Customer {
+        $customer = new CustomerStub($simpleAddresses, $logged, $guest);
+
+        foreach ($overrides as $property => $value) {
+            $customer->{$property} = $value;
+        }
+
+        return $customer;
+    }
+
+    /**
+     * @param array<string, mixed> $overrides
+     */
+    public static function cart(array $overrides = []): \Cart
+    {
+        $cart = new CartStub();
+
+        foreach ($overrides as $property => $value) {
+            $cart->{$property} = $value;
+        }
+
+        return $cart;
+    }
+
+    public static function pricedCart(float $total, array $overrides = []): \Cart
+    {
+        $cart = new PricedCartStub($total);
+
+        foreach ($overrides as $property => $value) {
+            $cart->{$property} = $value;
+        }
+
+        return $cart;
+    }
+
+    public static function virtualCart(bool $isVirtual, array $overrides = []): \Cart
+    {
+        $cart = new VirtualCartStub($isVirtual);
+
+        foreach ($overrides as $property => $value) {
+            $cart->{$property} = $value;
+        }
+
+        return $cart;
+    }
+
+    public static function smarty(): \Smarty
+    {
+        return new SmartyStub();
+    }
+
+    public static function shop(int $id = 1): object
+    {
+        return new ShopStub($id);
+    }
+
+    public static function translator(?callable $translator = null): object
+    {
+        return new TranslatorStub($translator);
+    }
+}
+
+final class ContextStub extends \Context
+{
+    public function __construct()
+    {
+    }
+}
+
+final class LanguageStub extends \Language
+{
+    public function __construct()
+    {
+    }
+}
+
+final class CountryStub extends \Country
+{
+    public function __construct()
+    {
+    }
+}
+
+class CartStub extends \Cart
+{
+    public function __construct()
+    {
+    }
+}
+
+final class PricedCartStub extends CartStub
+{
+    public function __construct(private readonly float $total)
+    {
+    }
+
+    public function getOrderTotal($withTaxes = true, $type = \Cart::BOTH, $products = null, $id_carrier = null, $use_cache = false, bool $keepOrderPrices = false)
+    {
+        return $this->total;
+    }
+}
+
+final class VirtualCartStub extends CartStub
+{
+    public function __construct(private readonly bool $virtual)
+    {
+    }
+
+    public function isVirtualCart()
+    {
+        return $this->virtual;
+    }
+}
+
+final class CustomerStub extends \Customer
+{
+    /**
+     * @param array<int, array<string, mixed>> $simpleAddresses
+     */
+    public function __construct(
+        private readonly array $simpleAddresses = [],
+        private readonly bool $logged = false,
+        private readonly bool $guest = false,
+    ) {
+    }
+
+    public function getSimpleAddresses($idLang = null): array
+    {
+        return $this->simpleAddresses;
+    }
+
+    public function getAddresses($idLang = null): array
+    {
+        return $this->simpleAddresses;
+    }
+
+    public function isGuest(): bool
+    {
+        return $this->guest;
+    }
+
+    public function isLogged($withGuest = false): bool
+    {
+        return $this->logged || ($withGuest && $this->guest);
+    }
+}
+
+final class SmartyStub extends \Smarty
+{
+    public function __construct()
+    {
+    }
+}
+
+final class ShopStub
+{
+    public function __construct(public int $id)
+    {
+    }
+}
+
+final class TranslatorStub
+{
+    /**
+     * @var callable|null
+     */
+    private $translatorCallback;
+
+    public function __construct(?callable $translator = null)
+    {
+        $this->translatorCallback = $translator;
+    }
+
+    public function trans(string $message, array $parameters = [], string $domain = ''): string
+    {
+        if ($this->translatorCallback !== null) {
+            return (string) call_user_func($this->translatorCallback, $message, $parameters, $domain);
+        }
+
+        return strtr($message, $parameters);
+    }
+}
diff --git a/tests/php/Fixtures/LegacyFormStubs.php b/tests/php/Fixtures/LegacyFormStubs.php
new file mode 100644
index 0000000..65431bf
--- /dev/null
+++ b/tests/php/Fixtures/LegacyFormStubs.php
@@ -0,0 +1,385 @@
+<?php
+
+if (!interface_exists('FormFormatterInterface', false)) {
+    interface FormFormatterInterface
+    {
+        public function getFormat();
+    }
+}
+
+if (!class_exists('FormField', false)) {
+    class FormField
+    {
+        public ?string $moduleName = null;
+        private string $name = '';
+        private string $type = 'text';
+        private bool $required = false;
+        private string $label = '';
+        private mixed $value = null;
+        private array $availableValues = [];
+        private ?int $minLength = null;
+        private ?int $maxLength = null;
+        private array $constraints = [];
+        private array $errors = [];
+
+        public function setName($name): self
+        {
+            $this->name = (string) $name;
+
+            return $this;
+        }
+
+        public function getName(): string
+        {
+            return $this->name;
+        }
+
+        public function setType($type): self
+        {
+            $this->type = (string) $type;
+
+            return $this;
+        }
+
+        public function getType(): string
+        {
+            return $this->type;
+        }
+
+        public function setRequired($required): self
+        {
+            $this->required = (bool) $required;
+
+            return $this;
+        }
+
+        public function isRequired(): bool
+        {
+            return $this->required;
+        }
+
+        public function setLabel($label): self
+        {
+            $this->label = (string) $label;
+
+            return $this;
+        }
+
+        public function getLabel(): string
+        {
+            return $this->label;
+        }
+
+        public function setValue($value): self
+        {
+            $this->value = $value;
+
+            return $this;
+        }
+
+        public function getValue(): mixed
+        {
+            return $this->value;
+        }
+
+        public function addAvailableValue($value, $label = null): self
+        {
+            $this->availableValues[$value] = $label ?? $value;
+
+            return $this;
+        }
+
+        public function setAvailableValues($availableValues): self
+        {
+            $this->availableValues = (array) $availableValues;
+
+            return $this;
+        }
+
+        public function getAvailableValues(): array
+        {
+            return $this->availableValues;
+        }
+
+        public function setMinLength($minLength): self
+        {
+            $this->minLength = (int) $minLength;
+
+            return $this;
+        }
+
+        public function getMinLength(): ?int
+        {
+            return $this->minLength;
+        }
+
+        public function setMaxLength($maxLength): self
+        {
+            $this->maxLength = (int) $maxLength;
+
+            return $this;
+        }
+
+        public function getMaxLength(): ?int
+        {
+            return $this->maxLength;
+        }
+
+        public function addConstraint($constraint): self
+        {
+            $this->constraints[] = $constraint;
+
+            return $this;
+        }
+
+        public function getConstraints(): array
+        {
+            return $this->constraints;
+        }
+
+        public function addError($error): self
+        {
+            $this->errors[] = $error;
+
+            return $this;
+        }
+
+        public function getErrors(): array
+        {
+            return $this->errors;
+        }
+
+        public function toArray(): array
+        {
+            return [
+                'name' => $this->name,
+                'type' => $this->type,
+                'required' => $this->required,
+                'label' => $this->label,
+                'value' => $this->value,
+                'availableValues' => $this->availableValues,
+                'minLength' => $this->minLength,
+                'maxLength' => $this->maxLength,
+                'constraints' => $this->constraints,
+                'errors' => $this->errors,
+            ];
+        }
+    }
+}
+
+if (!class_exists('Country', false)) {
+    class Country
+    {
+        public static array $registry = [];
+        public const GEOLOC_ALLOWED = 1;
+        public int $id = 0;
+        public bool $need_zip_code = false;
+        public string $zip_code_format = '';
+        public bool $need_identification_number = false;
+        public bool $contains_states = false;
+        public array $validZipCodes = [];
+
+        public function __construct(int $id = 0, int $idLang = 0)
+        {
+            if ($id > 0 && isset(self::$registry[$id])) {
+                $data = self::$registry[$id];
+                $this->id = $id;
+                $this->need_zip_code = (bool) ($data['need_zip_code'] ?? false);
+                $this->zip_code_format = (string) ($data['zip_code_format'] ?? '');
+                $this->need_identification_number = (bool) ($data['need_identification_number'] ?? false);
+                $this->contains_states = (bool) ($data['contains_states'] ?? false);
+                $this->validZipCodes = (array) ($data['validZipCodes'] ?? []);
+            }
+        }
+
+        public function checkZipCode($postcode): bool
+        {
+            return in_array((string) $postcode, $this->validZipCodes, true);
+        }
+
+        public static function getCountries($idLang = 0, $active = false): array
+        {
+            return array_map(static function (array $country, int $countryId): array {
+                return [
+                    'id_country' => $countryId,
+                    'name' => (string) ($country['name'] ?? ''),
+                ];
+            }, self::$registry, array_keys(self::$registry));
+        }
+    }
+}
+
+if (!class_exists('Address', false)) {
+    class Address
+    {
+        public static array $definition = ['fields' => []];
+        public $id = 0;
+        public $id_customer = 0;
+        public $id_country = 0;
+        public $id_state = 0;
+        public $alias = '';
+        public $firstname = '';
+        public $lastname = '';
+        public $address1 = '';
+        public $address2 = '';
+        public $postcode = '';
+        public $city = '';
+        public $phone = '';
+        public $dni = '';
+        public $company = '';
+
+        public function __construct($id = null, $idLang = null)
+        {
+            if ($id !== null) {
+                $this->id = (int) $id;
+            }
+        }
+    }
+}
+
+if (!class_exists('Customer', false)) {
+    class Customer
+    {
+        public static array $requiredFields = [];
+        public $id = 0;
+        public $is_guest = 0;
+        public $email = '';
+        public $firstname = '';
+        public $lastname = '';
+        public $id_country = 0;
+        public $id_gender = 0;
+        public $id_risk = 0;
+        public $passwd = '';
+
+        public function __construct($id = null)
+        {
+            if ($id !== null) {
+                $this->id = (int) $id;
+            }
+        }
+
+        public function isFieldRequired($fieldName): bool
+        {
+            return in_array($fieldName, self::$requiredFields, true);
+        }
+
+        public function isGuest(): bool
+        {
+            return false;
+        }
+
+        public function isLogged($withGuest = false): bool
+        {
+            return false;
+        }
+
+        public function getSimpleAddresses($idLang = null): array
+        {
+            return [];
+        }
+
+        public function getAddresses($idLang = null): array
+        {
+            return [];
+        }
+    }
+}
+
+if (!class_exists('Context', false)) {
+    class Context
+    {
+        public static ?self $instance = null;
+        public mixed $customer = null;
+        public mixed $cart = null;
+        public mixed $cookie = null;
+        public mixed $language = null;
+        public mixed $country = null;
+        public mixed $shop = null;
+        public mixed $smarty = null;
+        public mixed $link = null;
+        public mixed $controller = null;
+
+        public static function getContext(): self
+        {
+            if (self::$instance === null) {
+                self::$instance = new self();
+                self::$instance->customer = new class {
+                    public function isLogged($withGuest = false): bool
+                    {
+                        return false;
+                    }
+                };
+            }
+
+            return self::$instance;
+        }
+    }
+}
+
+if (!class_exists('Configuration', false)) {
+    class Configuration
+    {
+        public static array $values = [];
+
+        public static function get($key)
+        {
+            return self::$values[$key] ?? false;
+        }
+
+        public static function resetStaticCache(): void
+        {
+        }
+    }
+}
+
+if (!class_exists('Carrier', false)) {
+    class Carrier
+    {
+        public static function getDeliveredCountries($idLang = 0, $active = false, $groupByZone = false): array
+        {
+            return Country::getCountries($idLang, $active);
+        }
+    }
+}
+
+if (!class_exists('AddressFormat', false)) {
+    class AddressFormat
+    {
+        public static array $orderedFields = [];
+        public static array $requiredFields = [];
+
+        public static function getOrderedAddressFields($idCountry = 0, $splitAll = false, $cleaned = false): array
+        {
+            return self::$orderedFields;
+        }
+
+        public static function getFieldsRequired(): array
+        {
+            return self::$requiredFields;
+        }
+    }
+}
+
+if (!class_exists('State', false)) {
+    class State
+    {
+        public static array $statesByCountry = [];
+
+        public static function getStatesByIdCountry($idCountry, $active = false, $orderBy = null, $sort = 'ASC'): array
+        {
+            return self::$statesByCountry[(int) $idCountry] ?? [];
+        }
+    }
+}
+
+if (!class_exists('Hook', false)) {
+    class Hook
+    {
+        public static array $responses = [];
+
+        public static function exec($hookName, $hookArgs = [], $idModule = null, $arrayReturn = false)
+        {
+            return self::$responses[$hookName] ?? ($arrayReturn ? [] : null);
+        }
+    }
+}
diff --git a/tests/php/Integration/Checkout/Ajax/OpcAddressFormHandlerIntegrationTest.php b/tests/php/Integration/Checkout/Ajax/OpcAddressFormHandlerIntegrationTest.php
index 8a3d47a..2e1e372 100644
--- a/tests/php/Integration/Checkout/Ajax/OpcAddressFormHandlerIntegrationTest.php
+++ b/tests/php/Integration/Checkout/Ajax/OpcAddressFormHandlerIntegrationTest.php
@@ -32,13 +32,14 @@ public function testItLoadsAddressThenAppliesWhitelistedPayload(): void
     {
         $customer = $this->createCustomer($this->uniqueEmail('opc-address'));
         $address = $this->createAddressForCustomer((int) $customer->id);
+        self::getContext()->customer = $customer;
 
         $formSpy = new IntegrationOpcAddressFormSpy();
         $formSpy->templateVars = ['address_form' => '<form>ok</form>'];
         $handler = new OnePageCheckoutAddressFormHandler($formSpy);
 
         $response = $handler->getTemplateVariables([
-            'id_address' => (string) $address->id,
+            'id_address_delivery' => (string) $address->id,
             'id_country' => '8',
             'invoice_id_country' => '8',
             'use_same_address' => '1',
@@ -47,13 +48,15 @@ public function testItLoadsAddressThenAppliesWhitelistedPayload(): void
 
         self::assertSame([(int) $address->id], $formSpy->loadedAddressIds);
         self::assertSame([
+            ['customer_id' => (int) $customer->id],
             [
                 'id_country' => '8',
-                'invoice_id_country' => '8',
                 'use_same_address' => '1',
+                'id_address_delivery' => (string) $address->id,
             ],
         ], $formSpy->fillWithPayloads);
-        self::assertSame(['address_form' => '<form>ok</form>'], $response);
+        self::assertAddressSectionContext($response);
+        self::assertSame('<form>ok</form>', $response['address_form']);
     }
 
     public function testItDoesNotLoadAddressWhenIdIsNotPositive(): void
@@ -63,7 +66,7 @@ public function testItDoesNotLoadAddressWhenIdIsNotPositive(): void
         $handler = new OnePageCheckoutAddressFormHandler($formSpy);
 
         $response = $handler->getTemplateVariables([
-            'id_address' => '0',
+            'id_address_delivery' => '0',
             'id_country' => '8',
         ]);
 
@@ -71,7 +74,8 @@ public function testItDoesNotLoadAddressWhenIdIsNotPositive(): void
         self::assertSame([
             ['id_country' => '8'],
         ], $formSpy->fillWithPayloads);
-        self::assertSame(['address_form' => '<form>country-only</form>'], $response);
+        self::assertAddressSectionContext($response);
+        self::assertSame('<form>country-only</form>', $response['address_form']);
     }
 
     public function testItReturnsTemplateVariablesWithoutFormFillWhenPayloadIsIrrelevant(): void
@@ -86,7 +90,109 @@ public function testItReturnsTemplateVariablesWithoutFormFillWhenPayloadIsIrrele
 
         self::assertSame([], $formSpy->loadedAddressIds);
         self::assertSame([], $formSpy->fillWithPayloads);
-        self::assertSame(['address_form' => '<form>initial</form>'], $response);
+        self::assertAddressSectionContext($response);
+        self::assertSame('<form>initial</form>', $response['address_form']);
+    }
+
+    public function testItPreservesPositiveInvoiceAddressIdInRefreshPayload(): void
+    {
+        $customer = $this->createCustomer($this->uniqueEmail('opc-invoice'));
+        $invoiceAddress = $this->createAddressForCustomer((int) $customer->id);
+        self::getContext()->customer = $customer;
+
+        $formSpy = new IntegrationOpcAddressFormSpy();
+        $formSpy->templateVars = ['address_form' => '<form>invoice</form>'];
+        $handler = new OnePageCheckoutAddressFormHandler($formSpy);
+
+        $response = $handler->getTemplateVariables([
+            'id_address_invoice' => (string) $invoiceAddress->id,
+            'invoice_id_country' => '8',
+        ]);
+
+        self::assertSame([
+            ['customer_id' => (int) $customer->id],
+            [
+                'invoice_id_country' => '8',
+                'id_address_invoice' => (string) $invoiceAddress->id,
+            ],
+        ], $formSpy->fillWithPayloads);
+        self::assertAddressSectionContext($response);
+        self::assertSame('<form>invoice</form>', $response['address_form']);
+    }
+
+    public function testItRejectsForeignAddressOwnershipDuringRefresh(): void
+    {
+        $owner = $this->createCustomer($this->uniqueEmail('opc-owner'));
+        $foreignCustomer = $this->createCustomer($this->uniqueEmail('opc-foreign'));
+        $foreignAddress = $this->createAddressForCustomer((int) $foreignCustomer->id);
+        self::getContext()->customer = $owner;
+
+        $formSpy = new IntegrationOpcAddressFormSpy();
+        $formSpy->templateVars = ['address_form' => '<form>safe</form>'];
+        $handler = new OnePageCheckoutAddressFormHandler($formSpy);
+
+        $response = $handler->getTemplateVariables([
+            'id_address_delivery' => (string) $foreignAddress->id,
+            'id_country' => '8',
+        ]);
+
+        self::assertSame([], $formSpy->loadedAddressIds);
+        self::assertSame([
+            ['customer_id' => (int) $owner->id],
+            ['id_country' => '8'],
+        ], $formSpy->fillWithPayloads);
+        self::assertAddressSectionContext($response);
+        self::assertSame('<form>safe</form>', $response['address_form']);
+    }
+
+    public function testItFallsBackToDefaultCountryWhenCustomerHasNoSavedAddress(): void
+    {
+        $customer = $this->createCustomer($this->uniqueEmail('opc-empty-addresses'));
+        self::getContext()->customer = $customer;
+
+        $formSpy = new IntegrationOpcAddressFormSpy();
+        $formSpy->templateVars = ['address_form' => '<form>default-country</form>'];
+        $handler = new OnePageCheckoutAddressFormHandler($formSpy);
+
+        $response = $handler->getTemplateVariables([
+            'use_same_address' => '1',
+        ]);
+
+        self::assertSame([
+            ['customer_id' => (int) $customer->id],
+            [
+                'use_same_address' => '1',
+                'id_country' => (string) \Configuration::get('PS_COUNTRY_DEFAULT'),
+            ],
+        ], $formSpy->fillWithPayloads);
+        self::assertAddressSectionContext($response);
+        self::assertSame('<form>default-country</form>', $response['address_form']);
+    }
+
+    public function testItIgnoresInvoiceCountryWhenUseSameAddressIsEnabled(): void
+    {
+        $customer = $this->createCustomer($this->uniqueEmail('opc-same-address-country'));
+        self::getContext()->customer = $customer;
+
+        $formSpy = new IntegrationOpcAddressFormSpy();
+        $formSpy->templateVars = ['address_form' => '<form>same-address-country</form>'];
+        $handler = new OnePageCheckoutAddressFormHandler($formSpy);
+
+        $response = $handler->getTemplateVariables([
+            'id_country' => '21',
+            'invoice_id_country' => '8',
+            'use_same_address' => '1',
+        ]);
+
+        self::assertSame([
+            ['customer_id' => (int) $customer->id],
+            [
+                'id_country' => '21',
+                'use_same_address' => '1',
+            ],
+        ], $formSpy->fillWithPayloads);
+        self::assertAddressSectionContext($response);
+        self::assertSame('<form>same-address-country</form>', $response['address_form']);
     }
 
     private static function resetTables(): void
@@ -132,6 +238,18 @@ private function uniqueEmail(string $prefix): string
     {
         return sprintf('%s_%s@example.com', $prefix, uniqid('', true));
     }
+
+    /**
+     * @param array<string,mixed> $response
+     */
+    private static function assertAddressSectionContext(array $response): void
+    {
+        self::assertArrayHasKey('is_virtual_cart', $response);
+        self::assertArrayHasKey('cart', $response);
+        self::assertIsArray($response['cart']);
+        self::assertArrayHasKey('id_address_delivery', $response['cart']);
+        self::assertArrayHasKey('id_address_invoice', $response['cart']);
+    }
 }
 
 class IntegrationOpcAddressFormSpy extends OnePageCheckoutForm
@@ -162,6 +280,15 @@ public function fillFromAddress(\Address $address)
         return $this;
     }
 
+    public function fillFromCustomer(\Customer $customer)
+    {
+        $this->fillWithPayloads[] = [
+            'customer_id' => (int) $customer->id,
+        ];
+
+        return $this;
+    }
+
     public function fillWith(array $params = [])
     {
         $this->fillWithPayloads[] = $params;
diff --git a/tests/php/Integration/Checkout/Ajax/OpcAddressesListHandlerIntegrationTest.php b/tests/php/Integration/Checkout/Ajax/OpcAddressesListHandlerIntegrationTest.php
new file mode 100644
index 0000000..77928bc
--- /dev/null
+++ b/tests/php/Integration/Checkout/Ajax/OpcAddressesListHandlerIntegrationTest.php
@@ -0,0 +1,81 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Integration\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerContextResolver;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutAddressesListHandler;
+use Tests\Integration\Utility\ContextMockerTrait;
+use Tests\Resources\DatabaseDump;
+
+class OpcAddressesListHandlerIntegrationTest extends TestCase
+{
+    use ContextMockerTrait;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        self::mockContext();
+        DatabaseDump::restoreTables([
+            'configuration',
+            'customer',
+            'customer_group',
+            'address',
+        ]);
+        \Configuration::loadConfiguration();
+    }
+
+    public function testItReturnsCurrentCheckoutCustomerAddressListContext(): void
+    {
+        $customer = $this->createCustomer();
+        $firstAddress = $this->createAddressForCustomer((int) $customer->id, 'Home');
+        $secondAddress = $this->createAddressForCustomer((int) $customer->id, 'Office');
+
+        $context = self::getContext();
+        $context->customer = $customer;
+        $context->language = new \Language((int) \Configuration::get('PS_LANG_DEFAULT'));
+        $context->cart = new \Cart();
+        $context->cart->id_address_delivery = (int) $secondAddress->id;
+        $context->cart->id_address_invoice = (int) $firstAddress->id;
+
+        $handler = new OnePageCheckoutAddressesListHandler($context, new CheckoutCustomerContextResolver($context));
+        $response = $handler->handle();
+
+        self::assertTrue($response['success']);
+        self::assertSame(2, $response['address_count']);
+        self::assertSame((int) $secondAddress->id, (int) $response['selected_delivery_address']);
+        self::assertSame((int) $firstAddress->id, (int) $response['selected_invoice_address']);
+        self::assertCount(2, $response['customer']['addresses']);
+    }
+
+    private function createCustomer(): \Customer
+    {
+        $customer = new \Customer();
+        $customer->firstname = 'Integration';
+        $customer->lastname = 'Customer';
+        $customer->email = sprintf('opc-addresses-%s@example.com', uniqid('', true));
+        $customer->is_guest = true;
+        $customer->passwd = \Tools::hash('integration-password');
+        self::assertTrue($customer->save());
+
+        return $customer;
+    }
+
+    private function createAddressForCustomer(int $customerId, string $alias): \Address
+    {
+        $address = new \Address();
+        $address->id_customer = $customerId;
+        $address->id_country = (int) \Configuration::get('PS_COUNTRY_DEFAULT');
+        $address->firstname = 'Integration';
+        $address->lastname = 'Customer';
+        $address->address1 = '1 rue Integration';
+        $address->alias = $alias . '_' . uniqid('', true);
+        $address->city = 'Paris';
+        self::assertTrue($address->save());
+
+        return $address;
+    }
+}
diff --git a/tests/php/Integration/Checkout/Ajax/OpcDeleteAddressHandlerIntegrationTest.php b/tests/php/Integration/Checkout/Ajax/OpcDeleteAddressHandlerIntegrationTest.php
new file mode 100644
index 0000000..2779d22
--- /dev/null
+++ b/tests/php/Integration/Checkout/Ajax/OpcDeleteAddressHandlerIntegrationTest.php
@@ -0,0 +1,114 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Integration\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerContextResolver;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutDeleteAddressHandler;
+use Symfony\Contracts\Translation\TranslatorInterface;
+use Tests\Integration\Utility\ContextMockerTrait;
+use Tests\Resources\DatabaseDump;
+
+class OpcDeleteAddressHandlerIntegrationTest extends TestCase
+{
+    use ContextMockerTrait;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        self::mockContext();
+        DatabaseDump::restoreTables([
+            'configuration',
+            'customer',
+            'customer_group',
+            'address',
+            'cart',
+        ]);
+        \Configuration::loadConfiguration();
+    }
+
+    public function testItSynchronizesCheckoutSessionAfterDeletingActiveAddress(): void
+    {
+        $customer = $this->createCustomer();
+        $context = self::getContext();
+        $context->customer = $customer;
+        $context->language = new \Language((int) \Configuration::get('PS_LANG_DEFAULT'));
+
+        $activeAddress = $this->createAddress($customer, 'Active delivery');
+        $fallbackAddress = $this->createAddress($customer, 'Fallback delivery');
+
+        $cart = new \Cart();
+        $cart->id_currency = (int) \Configuration::get('PS_CURRENCY_DEFAULT');
+        $cart->id_lang = (int) \Configuration::get('PS_LANG_DEFAULT');
+        $cart->id_shop_group = 1;
+        $cart->id_shop = 1;
+        $cart->id_customer = (int) $customer->id;
+        $cart->id_address_delivery = (int) $activeAddress->id;
+        $cart->id_address_invoice = (int) $activeAddress->id;
+        self::assertTrue($cart->add());
+        $context->cart = $cart;
+
+        $translator = $this->createMock(TranslatorInterface::class);
+        $translator->method('trans')->willReturnArgument(0);
+
+        $handler = new OnePageCheckoutDeleteAddressHandler($context, $translator, new CheckoutCustomerContextResolver($context));
+        $response = $handler->handle([
+            'id_address' => (string) $activeAddress->id,
+        ]);
+
+        self::assertTrue($response['success'], var_export($response, true));
+
+        $freshCart = new \Cart((int) $cart->id);
+        self::assertSame((int) $fallbackAddress->id, (int) $freshCart->id_address_delivery);
+        self::assertSame((int) $fallbackAddress->id, (int) $freshCart->id_address_invoice);
+
+        $checkoutSession = $this->createCheckoutSession($context, $translator);
+        self::assertSame((int) $fallbackAddress->id, (int) $checkoutSession->getIdAddressDelivery());
+        self::assertSame((int) $fallbackAddress->id, (int) $checkoutSession->getIdAddressInvoice());
+    }
+
+    private function createCustomer(): \Customer
+    {
+        $customer = new \Customer();
+        $customer->firstname = 'Integration';
+        $customer->lastname = 'Customer';
+        $customer->email = sprintf('opc-delete-%s@example.com', uniqid('', true));
+        $customer->is_guest = false;
+        $customer->passwd = \Tools::hash('integration-password');
+        self::assertTrue($customer->save());
+
+        return $customer;
+    }
+
+    private function createAddress(\Customer $customer, string $alias): \Address
+    {
+        $address = new \Address();
+        $address->id_customer = (int) $customer->id;
+        $address->alias = $alias;
+        $address->firstname = $customer->firstname;
+        $address->lastname = $customer->lastname;
+        $address->address1 = '1 rue Integration';
+        $address->city = 'Paris';
+        $address->postcode = '75001';
+        $address->id_country = (int) \Configuration::get('PS_COUNTRY_DEFAULT');
+        self::assertTrue($address->add());
+
+        return $address;
+    }
+
+    private function createCheckoutSession(\Context $context, TranslatorInterface $translator): \CheckoutSession
+    {
+        return new \CheckoutSession(
+            $context,
+            new \DeliveryOptionsFinder(
+                $context,
+                $translator,
+                new \PrestaShop\PrestaShop\Adapter\Presenter\Object\ObjectPresenter(),
+                new \PrestaShop\PrestaShop\Adapter\Product\PriceFormatter()
+            )
+        );
+    }
+}
diff --git a/tests/php/Integration/Checkout/Ajax/OpcGuestInitHandlerGuestFlowIntegrationTest.php b/tests/php/Integration/Checkout/Ajax/OpcGuestInitHandlerGuestFlowIntegrationTest.php
index 66ae405..ad47b21 100644
--- a/tests/php/Integration/Checkout/Ajax/OpcGuestInitHandlerGuestFlowIntegrationTest.php
+++ b/tests/php/Integration/Checkout/Ajax/OpcGuestInitHandlerGuestFlowIntegrationTest.php
@@ -43,14 +43,14 @@ public function testItUsesFreshCartOwnerWhenContextCartSnapshotIsOutdated(): voi
         $this->scenarioItUsesFreshCartOwnerWhenContextCartSnapshotIsOutdated();
     }
 
-    public function testItUsesContextCartOwnerWhenFreshCartRowIsMissing(): void
+    public function testItReturnsErrorWhenFreshCartRowIsMissing(): void
     {
-        $this->scenarioItUsesContextCartOwnerWhenFreshCartRowIsMissing();
+        $this->scenarioItReturnsErrorWhenFreshCartRowIsMissing();
     }
 
-    public function testItReturnsNoopWhenEmailBelongsToExistingAccountAndNoGuestIsLinked(): void
+    public function testItFallsBackToGuestCreationWhenEmailBelongsToExistingAccountAndNoGuestIsLinked(): void
     {
-        $this->scenarioItReturnsNoopWhenEmailBelongsToExistingAccountAndNoGuestIsLinked();
+        $this->scenarioItFallsBackToGuestCreationWhenEmailBelongsToExistingAccountAndNoGuestIsLinked();
     }
 
     public function testItCreatesGuestAndClaimsUnassignedCart(): void
@@ -68,6 +68,11 @@ public function testItUpdatesExistingGuestEmailWithoutCreatingNewCustomer(): voi
         $this->scenarioItUpdatesExistingGuestEmailWithoutCreatingNewCustomer();
     }
 
+    public function testItCreatesNewGuestForNewAnonymousCartEvenWhenGuestEmailAlreadyExists(): void
+    {
+        $this->scenarioItCreatesNewGuestForNewAnonymousCartEvenWhenGuestEmailAlreadyExists();
+    }
+
     public function testItUpdatesCartOwnerGuestAndRealignsContextWhenUpdatingEmailFromMismatchedContextCustomer(): void
     {
         $this->scenarioItUpdatesCartOwnerGuestAndRealignsContextWhenUpdatingEmailFromMismatchedContextCustomer();
diff --git a/tests/php/Integration/Checkout/Ajax/OpcGuestInitHandlerIntegrationTestCase.php b/tests/php/Integration/Checkout/Ajax/OpcGuestInitHandlerIntegrationTestCase.php
index bffe87f..3c9c04c 100644
--- a/tests/php/Integration/Checkout/Ajax/OpcGuestInitHandlerIntegrationTestCase.php
+++ b/tests/php/Integration/Checkout/Ajax/OpcGuestInitHandlerIntegrationTestCase.php
@@ -307,7 +307,7 @@ protected function scenarioItUsesFreshCartOwnerWhenContextCartSnapshotIsOutdated
         self::assertSame((int) $winner->id, $response['id_customer']);
     }
 
-    protected function scenarioItUsesContextCartOwnerWhenFreshCartRowIsMissing(): void
+    protected function scenarioItReturnsErrorWhenFreshCartRowIsMissing(): void
     {
         $winner = $this->createCustomer($this->uniqueEmail('missing-row-owner'), false);
         $persistedCart = $this->prepareEligibleCartContext((int) $winner->id);
@@ -330,12 +330,14 @@ protected function scenarioItUsesContextCartOwnerWhenFreshCartRowIsMissing(): vo
             'token' => self::EXPECTED_TOKEN,
         ]);
 
-        self::assertTrue($response['success']);
+        self::assertFalse($response['success']);
+        self::assertArrayHasKey('', $response['errors']);
+        self::assertNotEmpty($response['errors']['']);
         self::assertFalse($response['customer_created']);
-        self::assertSame((int) $winner->id, $response['id_customer']);
+        self::assertSame(0, $response['id_customer']);
     }
 
-    protected function scenarioItReturnsNoopWhenEmailBelongsToExistingAccountAndNoGuestIsLinked(): void
+    protected function scenarioItFallsBackToGuestCreationWhenEmailBelongsToExistingAccountAndNoGuestIsLinked(): void
     {
         $registered = $this->createCustomer($this->uniqueEmail('existing-no-guest-linked'), false);
         $this->prepareEligibleCartContext(0);
@@ -343,8 +345,16 @@ protected function scenarioItReturnsNoopWhenEmailBelongsToExistingAccountAndNoGu
 
         $opcForm = $this->buildOpcFormMock();
         $opcForm
-            ->expects($this->never())
+            ->expects($this->once())
             ->method('submitGuestInit')
+            ->willReturn(false)
+        ;
+        $opcForm
+            ->expects($this->once())
+            ->method('getErrors')
+            ->willReturn([
+                'email' => ['Unable to save guest customer'],
+            ])
         ;
 
         $handler = $this->buildHandler($opcForm);
@@ -354,9 +364,8 @@ protected function scenarioItReturnsNoopWhenEmailBelongsToExistingAccountAndNoGu
             'token' => self::EXPECTED_TOKEN,
         ]);
 
-        self::assertTrue($response['success']);
-        self::assertFalse($response['customer_created']);
-        self::assertSame(0, $response['id_customer']);
+        self::assertFalse($response['success']);
+        self::assertSame(['Unable to save guest customer'], $response['errors']['email']);
     }
 
     protected function scenarioItCreatesGuestAndClaimsUnassignedCart(): void
@@ -519,6 +528,42 @@ protected function scenarioItUpdatesExistingGuestEmailWithoutCreatingNewCustomer
         self::assertSame($updatedEmail, (string) $freshGuest->email);
     }
 
+    protected function scenarioItCreatesNewGuestForNewAnonymousCartEvenWhenGuestEmailAlreadyExists(): void
+    {
+        $guest = $this->createCustomer($this->uniqueEmail('existing-guest-anonymous-cart'), true);
+        $persistedCart = $this->prepareEligibleCartContext(0);
+        self::getContext()->customer = new \Customer();
+
+        $createdGuest = $this->createCustomer((string) $guest->email, true);
+
+        $opcForm = $this->buildOpcFormMock();
+        $opcForm
+            ->expects($this->once())
+            ->method('submitGuestInit')
+            ->willReturnCallback(function () use ($createdGuest): bool {
+                self::getContext()->customer = $createdGuest;
+
+                return true;
+            })
+        ;
+
+        $handler = $this->buildHandler($opcForm);
+
+        $response = $handler->handle([
+            'email' => (string) $guest->email,
+            'token' => self::EXPECTED_TOKEN,
+        ]);
+
+        self::assertTrue($response['success']);
+        self::assertTrue($response['customer_created']);
+        self::assertSame((int) $createdGuest->id, $response['id_customer']);
+        self::assertSame((int) $createdGuest->id, $this->getPersistedCartCustomerId((int) $persistedCart->id));
+        self::assertNotSame((int) $guest->id, (int) $createdGuest->id);
+        self::assertSame((int) $createdGuest->id, (int) self::getContext()->customer->id);
+        self::assertSame((int) $createdGuest->id, (int) self::getContext()->cookie->id_customer);
+        self::assertSame((string) $guest->email, (string) self::getContext()->cookie->email);
+    }
+
     protected function scenarioItUpdatesCartOwnerGuestAndRealignsContextWhenUpdatingEmailFromMismatchedContextCustomer(): void
     {
         $guestOwner = $this->createCustomer($this->uniqueEmail('guest-owner-mismatch'), true);
@@ -1227,8 +1272,16 @@ protected function scenarioItReturnsErrorWhenCartOwnerReferenceIsStaleDuringGues
 
         $opcForm = $this->buildOpcFormMock();
         $opcForm
-            ->expects($this->never())
+            ->expects($this->once())
             ->method('submitGuestInit')
+            ->willReturn(false)
+        ;
+        $opcForm
+            ->expects($this->once())
+            ->method('getErrors')
+            ->willReturn([
+                'email' => ['Unable to save guest customer'],
+            ])
         ;
 
         $handler = $this->buildHandler($opcForm);
@@ -1239,8 +1292,7 @@ protected function scenarioItReturnsErrorWhenCartOwnerReferenceIsStaleDuringGues
         ]);
 
         self::assertFalse($response['success']);
-        self::assertArrayHasKey('', $response['errors']);
-        self::assertNotEmpty($response['errors']['']);
+        self::assertSame(['Unable to save guest customer'], $response['errors']['email']);
         self::assertSame(self::EXPECTED_TOKEN, $response['token']);
         self::assertSame(self::EXPECTED_TOKEN, $response['static_token']);
     }
diff --git a/tests/php/Integration/Checkout/Ajax/OpcPaymentMethodsHandlerIntegrationTest.php b/tests/php/Integration/Checkout/Ajax/OpcPaymentMethodsHandlerIntegrationTest.php
new file mode 100644
index 0000000..f0c5372
--- /dev/null
+++ b/tests/php/Integration/Checkout/Ajax/OpcPaymentMethodsHandlerIntegrationTest.php
@@ -0,0 +1,450 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Integration\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutPaymentMethodsHandler;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\PaymentSelectionKeyBuilder;
+use Tests\Integration\Utility\ContextMockerTrait;
+use Tests\Resources\DatabaseDump;
+
+class OpcPaymentMethodsHandlerIntegrationTest extends TestCase
+{
+    use ContextMockerTrait;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        self::mockContext();
+        DatabaseDump::restoreTables([
+            'configuration',
+            'module_country',
+            'customer',
+            'customer_group',
+            'address',
+        ]);
+        \Configuration::loadConfiguration();
+    }
+
+    public function testItReturnsPaymentOptionsAndSelectedModuleForPaidCart(): void
+    {
+        $paymentOption = [
+            'module_name' => 'ps_wirepayment',
+            'call_to_action_text' => 'Wire payment',
+            'action' => '/module/ps_wirepayment/validation',
+        ];
+        $selectionKey = (new PaymentSelectionKeyBuilder())->buildSelectionKey($paymentOption);
+
+        $context = self::getContext();
+        $context->cart = new class extends \Cart {
+            public function __construct()
+            {
+                $this->id = 1;
+            }
+
+            public function getOrderTotal($withTaxes = true, $type = \Cart::BOTH, $products = null, $id_carrier = null, $use_cache = false, bool $keepOrderPrices = false)
+            {
+                return 42.0;
+            }
+        };
+        $context->cookie->__set('opc_selected_payment_module', 'ps_wirepayment');
+        $context->cookie->__set('opc_selected_payment_selection_key', $selectionKey);
+
+        $finder = new class($paymentOption) extends \PaymentOptionsFinder {
+            private array $paymentOption;
+
+            public function __construct(array $paymentOption)
+            {
+                $this->paymentOption = $paymentOption;
+            }
+
+            public function present($free = false)
+            {
+                return $free ? [] : ['ps_wirepayment' => [0 => $this->paymentOption]];
+            }
+        };
+
+        $handler = new OnePageCheckoutPaymentMethodsHandler($context, $finder);
+        $response = $handler->handle();
+
+        self::assertTrue($response['success']);
+        self::assertFalse($response['is_free']);
+        self::assertSame('ps_wirepayment', $response['selected_payment_module']);
+        self::assertSame($selectionKey, $response['selected_payment_selection_key']);
+        self::assertSame('ps_wirepayment', $response['payment_options']['ps_wirepayment'][0]['module_name']);
+        self::assertNotSame('', $response['payment_options']['ps_wirepayment'][0]['selection_key']);
+    }
+
+    public function testItFiltersPaymentOptionsByResolvedDeliveryCountry(): void
+    {
+        $context = self::getContext();
+        $context->cart = new class extends \Cart {
+            public function __construct()
+            {
+                $this->id = 1;
+            }
+
+            public function getOrderTotal($withTaxes = true, $type = \Cart::BOTH, $products = null, $id_carrier = null, $use_cache = false, bool $keepOrderPrices = false)
+            {
+                return 42.0;
+            }
+        };
+        $context->country = new \Country((int) \Country::getByIso('FR'));
+
+        $finder = new class extends \PaymentOptionsFinder {
+            public function __construct()
+            {
+            }
+
+            public function present($free = false)
+            {
+                return [
+                    'ps_wirepayment' => [
+                        0 => [
+                            'module_name' => 'ps_wirepayment',
+                            'call_to_action_text' => 'Wire payment',
+                            'action' => '/module/ps_wirepayment/validation',
+                        ],
+                    ],
+                    'ps_checkpayment' => [
+                        0 => [
+                            'module_name' => 'ps_checkpayment',
+                            'call_to_action_text' => 'Check payment',
+                            'action' => '/module/ps_checkpayment/validation',
+                        ],
+                    ],
+                ];
+            }
+        };
+
+        $this->configureModuleCountryRestriction('ps_wirepayment', ['FR']);
+        $this->configureModuleCountryRestriction('ps_checkpayment', ['US']);
+
+        $handler = new OnePageCheckoutPaymentMethodsHandler($context, $finder);
+
+        $franceResponse = $handler->handle([
+            'id_country' => (string) \Country::getByIso('FR'),
+        ]);
+        self::assertArrayHasKey('ps_wirepayment', $franceResponse['payment_options']);
+        self::assertArrayNotHasKey('ps_checkpayment', $franceResponse['payment_options']);
+        self::assertSame((int) \Country::getByIso('FR'), (int) $context->country->id);
+
+        $usResponse = $handler->handle([
+            'id_country' => (string) \Country::getByIso('US'),
+        ]);
+        self::assertArrayNotHasKey('ps_wirepayment', $usResponse['payment_options']);
+        self::assertArrayHasKey('ps_checkpayment', $usResponse['payment_options']);
+        self::assertSame((int) \Country::getByIso('FR'), (int) $context->country->id);
+    }
+
+    public function testItFiltersPaymentOptionsByResolvedInvoiceCountryWhenTaxesUseInvoiceAddress(): void
+    {
+        \Configuration::updateValue('PS_TAX_ADDRESS_TYPE', 'id_address_invoice');
+
+        $context = self::getContext();
+        $context->cart = new class extends \Cart {
+            public function __construct()
+            {
+                $this->id = 1;
+                $this->id_address_delivery = 0;
+                $this->id_address_invoice = 0;
+            }
+
+            public function getOrderTotal($withTaxes = true, $type = \Cart::BOTH, $products = null, $id_carrier = null, $use_cache = false, bool $keepOrderPrices = false)
+            {
+                return 42.0;
+            }
+        };
+        $context->country = new \Country((int) \Country::getByIso('FR'));
+
+        $finder = new class extends \PaymentOptionsFinder {
+            public function __construct()
+            {
+            }
+
+            public function present($free = false)
+            {
+                return [
+                    'ps_wirepayment' => [
+                        0 => [
+                            'module_name' => 'ps_wirepayment',
+                            'call_to_action_text' => 'Wire payment',
+                            'action' => '/module/ps_wirepayment/validation',
+                        ],
+                    ],
+                    'ps_checkpayment' => [
+                        0 => [
+                            'module_name' => 'ps_checkpayment',
+                            'call_to_action_text' => 'Check payment',
+                            'action' => '/module/ps_checkpayment/validation',
+                        ],
+                    ],
+                ];
+            }
+        };
+
+        $this->configureModuleCountryRestriction('ps_wirepayment', ['FR']);
+        $this->configureModuleCountryRestriction('ps_checkpayment', ['US']);
+
+        $handler = new OnePageCheckoutPaymentMethodsHandler($context, $finder);
+        $response = $handler->handle([
+            'id_country' => (string) \Country::getByIso('FR'),
+            'invoice_id_country' => (string) \Country::getByIso('US'),
+        ]);
+
+        self::assertArrayNotHasKey('ps_wirepayment', $response['payment_options']);
+        self::assertArrayHasKey('ps_checkpayment', $response['payment_options']);
+        self::assertSame((int) \Country::getByIso('FR'), (int) $context->country->id);
+    }
+
+    public function testItFiltersPaymentOptionsByPersistedDeliveryAddressCountry(): void
+    {
+        $customer = $this->createCustomer('opc-payment-country');
+        $usAddress = $this->createAddressForCustomer((int) $customer->id, 'US');
+
+        $context = self::getContext();
+        $context->cart = new class((int) $usAddress->id) extends \Cart {
+            public function __construct(int $deliveryAddressId)
+            {
+                $this->id = 1;
+                $this->id_address_delivery = $deliveryAddressId;
+            }
+
+            public function getOrderTotal($withTaxes = true, $type = \Cart::BOTH, $products = null, $id_carrier = null, $use_cache = false, bool $keepOrderPrices = false)
+            {
+                return 42.0;
+            }
+        };
+        $context->country = new \Country((int) \Country::getByIso('FR'));
+
+        $finder = new class extends \PaymentOptionsFinder {
+            public function __construct()
+            {
+            }
+
+            public function present($free = false)
+            {
+                return [
+                    'ps_wirepayment' => [[
+                        'module_name' => 'ps_wirepayment',
+                        'call_to_action_text' => 'Wire payment',
+                        'action' => '/module/ps_wirepayment/validation',
+                    ]],
+                    'ps_checkpayment' => [[
+                        'module_name' => 'ps_checkpayment',
+                        'call_to_action_text' => 'Check payment',
+                        'action' => '/module/ps_checkpayment/validation',
+                    ]],
+                ];
+            }
+        };
+
+        $this->configureModuleCountryRestriction('ps_wirepayment', ['FR']);
+        $this->configureModuleCountryRestriction('ps_checkpayment', ['US']);
+
+        $handler = new OnePageCheckoutPaymentMethodsHandler($context, $finder);
+        $response = $handler->handle();
+
+        self::assertArrayNotHasKey('ps_wirepayment', $response['payment_options']);
+        self::assertArrayHasKey('ps_checkpayment', $response['payment_options']);
+        self::assertSame((int) \Country::getByIso('FR'), (int) $context->country->id);
+    }
+
+    public function testItPrefersExplicitDeliveryAddressSelectionWhenTaxesUseDeliveryAddress(): void
+    {
+        \Configuration::updateValue('PS_TAX_ADDRESS_TYPE', 'id_address_delivery');
+
+        $customer = $this->createCustomer('opc-payment-explicit-delivery');
+        $usAddress = $this->createAddressForCustomer((int) $customer->id, 'US');
+
+        $context = self::getContext();
+        $context->cart = new class extends \Cart {
+            public function __construct()
+            {
+                $this->id = 1;
+                $this->id_address_delivery = 0;
+                $this->id_address_invoice = 0;
+            }
+
+            public function getOrderTotal($withTaxes = true, $type = \Cart::BOTH, $products = null, $id_carrier = null, $use_cache = false, bool $keepOrderPrices = false)
+            {
+                return 42.0;
+            }
+        };
+        $context->country = new \Country((int) \Country::getByIso('FR'));
+
+        $finder = new class extends \PaymentOptionsFinder {
+            public function __construct()
+            {
+            }
+
+            public function present($free = false)
+            {
+                return [
+                    'ps_wirepayment' => [[
+                        'module_name' => 'ps_wirepayment',
+                        'call_to_action_text' => 'Wire payment',
+                        'action' => '/module/ps_wirepayment/validation',
+                    ]],
+                    'ps_checkpayment' => [[
+                        'module_name' => 'ps_checkpayment',
+                        'call_to_action_text' => 'Check payment',
+                        'action' => '/module/ps_checkpayment/validation',
+                    ]],
+                ];
+            }
+        };
+
+        $this->configureModuleCountryRestriction('ps_wirepayment', ['FR']);
+        $this->configureModuleCountryRestriction('ps_checkpayment', ['US']);
+
+        $handler = new OnePageCheckoutPaymentMethodsHandler($context, $finder);
+        $response = $handler->handle([
+            'id_address_delivery' => (string) $usAddress->id,
+            'invoice_id_country' => (string) \Country::getByIso('FR'),
+        ]);
+
+        self::assertArrayNotHasKey('ps_wirepayment', $response['payment_options']);
+        self::assertArrayHasKey('ps_checkpayment', $response['payment_options']);
+        self::assertSame((int) \Country::getByIso('FR'), (int) $context->country->id);
+    }
+
+    public function testItClearsPersistedPaymentSelectionWhenCountryFilteringMakesItInvalid(): void
+    {
+        $context = self::getContext();
+        $context->cart = new class extends \Cart {
+            public function __construct()
+            {
+                $this->id = 1;
+            }
+
+            public function getOrderTotal($withTaxes = true, $type = \Cart::BOTH, $products = null, $id_carrier = null, $use_cache = false, bool $keepOrderPrices = false)
+            {
+                return 42.0;
+            }
+        };
+        $context->country = new \Country((int) \Country::getByIso('FR'));
+        $context->cookie->__set('opc_selected_payment_option', 'payment-option-1');
+        $context->cookie->__set('opc_selected_payment_module', 'ps_wirepayment');
+        $context->cookie->__set('opc_selected_payment_selection_key', 'ps_wirepayment::selection');
+
+        $finder = new class extends \PaymentOptionsFinder {
+            public function __construct()
+            {
+            }
+
+            public function present($free = false)
+            {
+                return [
+                    'ps_wirepayment' => [
+                        0 => [
+                            'module_name' => 'ps_wirepayment',
+                            'call_to_action_text' => 'Wire payment',
+                            'action' => '/module/ps_wirepayment/validation',
+                        ],
+                    ],
+                    'ps_checkpayment' => [
+                        0 => [
+                            'module_name' => 'ps_checkpayment',
+                            'call_to_action_text' => 'Check payment',
+                            'action' => '/module/ps_checkpayment/validation',
+                        ],
+                    ],
+                ];
+            }
+        };
+
+        $this->configureModuleCountryRestriction('ps_wirepayment', ['FR']);
+        $this->configureModuleCountryRestriction('ps_checkpayment', ['US']);
+
+        $handler = new OnePageCheckoutPaymentMethodsHandler($context, $finder);
+        $response = $handler->handle([
+            'id_country' => (string) \Country::getByIso('US'),
+        ]);
+
+        self::assertSame('', $response['selected_payment_module']);
+        self::assertSame('', $response['selected_payment_selection_key']);
+        self::assertSame('', (string) $context->cookie->__get('opc_selected_payment_option'));
+        self::assertSame('', (string) $context->cookie->__get('opc_selected_payment_module'));
+        self::assertSame('', (string) $context->cookie->__get('opc_selected_payment_selection_key'));
+        self::assertArrayNotHasKey('ps_wirepayment', $response['payment_options']);
+        self::assertArrayHasKey('ps_checkpayment', $response['payment_options']);
+    }
+
+    public function testItReturnsStructuredErrorWhenCartIsMissing(): void
+    {
+        $context = self::getContext();
+        $context->cart = null;
+
+        $handler = new OnePageCheckoutPaymentMethodsHandler($context);
+        $response = $handler->handle();
+
+        self::assertFalse($response['success']);
+        self::assertArrayHasKey('errors', $response);
+    }
+
+    /**
+     * @param string[] $countryIsoCodes
+     */
+    private function configureModuleCountryRestriction(string $moduleName, array $countryIsoCodes): void
+    {
+        $moduleId = (int) \Module::getModuleIdByName($moduleName);
+        if ($moduleId <= 0) {
+            self::assertTrue(\Db::getInstance()->insert('module', [
+                'name' => pSQL($moduleName),
+                'active' => 1,
+            ]));
+            $moduleId = (int) \Db::getInstance()->Insert_ID();
+        }
+
+        self::assertGreaterThan(0, $moduleId, sprintf('Unable to resolve module "%s".', $moduleName));
+
+        $shopId = (int) self::getContext()->shop->id;
+        \Db::getInstance()->delete('module_country', sprintf('id_module = %d AND id_shop = %d', $moduleId, $shopId));
+
+        foreach ($countryIsoCodes as $isoCode) {
+            $countryId = (int) \Country::getByIso($isoCode);
+            self::assertGreaterThan(0, $countryId, sprintf('Unable to resolve country "%s".', $isoCode));
+
+            self::assertTrue(\Db::getInstance()->insert('module_country', [
+                'id_module' => $moduleId,
+                'id_shop' => $shopId,
+                'id_country' => $countryId,
+            ]));
+        }
+    }
+
+    private function createCustomer(string $emailPrefix): \Customer
+    {
+        $customer = new \Customer();
+        $customer->firstname = 'Payment';
+        $customer->lastname = 'Customer';
+        $customer->email = sprintf('%s_%s@example.com', $emailPrefix, uniqid('', true));
+        $customer->is_guest = false;
+        $customer->passwd = \Tools::hash('payment-test-password');
+
+        self::assertTrue($customer->save());
+
+        return $customer;
+    }
+
+    private function createAddressForCustomer(int $customerId, string $countryIso): \Address
+    {
+        $address = new \Address();
+        $address->id_customer = $customerId;
+        $address->id_country = (int) \Country::getByIso($countryIso);
+        $address->firstname = 'Payment';
+        $address->lastname = 'Customer';
+        $address->address1 = '1 rue Payment';
+        $address->alias = 'payment_' . uniqid('', true);
+        $address->postcode = $countryIso === 'US' ? '10001' : '75001';
+        $address->city = $countryIso === 'US' ? 'New York' : 'Paris';
+
+        self::assertTrue($address->save());
+
+        return $address;
+    }
+}
diff --git a/tests/php/Integration/Checkout/Ajax/OpcSaveAddressHandlerIntegrationTest.php b/tests/php/Integration/Checkout/Ajax/OpcSaveAddressHandlerIntegrationTest.php
new file mode 100644
index 0000000..7b4c60a
--- /dev/null
+++ b/tests/php/Integration/Checkout/Ajax/OpcSaveAddressHandlerIntegrationTest.php
@@ -0,0 +1,318 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Integration\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerContextResolver;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutSaveAddressHandler;
+use Symfony\Contracts\Translation\TranslatorInterface;
+use Tests\Integration\Utility\ContextMockerTrait;
+use Tests\Resources\DatabaseDump;
+
+class OpcSaveAddressHandlerIntegrationTest extends TestCase
+{
+    use ContextMockerTrait;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        self::mockContext();
+        DatabaseDump::restoreTables([
+            'configuration',
+            'customer',
+            'customer_group',
+            'address',
+            'cart',
+        ]);
+        \Configuration::loadConfiguration();
+    }
+
+    public function testItCreatesDeliveryAddressAndUpdatesCart(): void
+    {
+        $customer = $this->createCustomer();
+        $cart = $this->createCartForCustomer($customer);
+        $context = $this->createCheckoutContext($customer, $cart);
+        $translator = $this->createTranslator();
+        $countryId = (int) \Configuration::get('PS_COUNTRY_DEFAULT');
+        $states = \State::getStatesByIdCountry($countryId);
+        $defaultStateId = !empty($states) ? (int) $states[0]['id_state'] : 0;
+
+        $handler = $this->createHandler($context, $translator);
+        $response = $handler->handle([
+            'address_type' => 'delivery',
+            'firstname' => 'Integration',
+            'lastname' => 'Customer',
+            'address1' => '1 rue Integration',
+            'city' => 'Paris',
+            'postcode' => '75001',
+            'id_country' => (string) $countryId,
+            'id_state' => $defaultStateId > 0 ? (string) $defaultStateId : '',
+            'alias' => 'Home',
+            'use_same_address' => '1',
+        ]);
+
+        self::assertSame(['success' => true], $response, var_export($response, true));
+
+        $freshCart = new \Cart((int) $cart->id);
+        self::assertGreaterThan(0, (int) $freshCart->id_address_delivery);
+        self::assertSame((int) $freshCart->id_address_delivery, (int) $freshCart->id_address_invoice);
+
+        $checkoutSession = $this->createCheckoutSession($context, $translator);
+        self::assertSame((int) $freshCart->id_address_delivery, (int) $checkoutSession->getIdAddressDelivery());
+        self::assertSame((int) $freshCart->id_address_invoice, (int) $checkoutSession->getIdAddressInvoice());
+    }
+
+    public function testItCreatesDeliveryAddressWithoutAliasAndUsesTheFallbackAlias(): void
+    {
+        $customer = $this->createCustomer();
+        $cart = $this->createCartForCustomer($customer);
+        $context = $this->createCheckoutContext($customer, $cart);
+        $translator = $this->createTranslator();
+        $countryId = (int) \Configuration::get('PS_COUNTRY_DEFAULT');
+        $defaultStateId = $this->getFirstStateIdForCountry($countryId);
+
+        $handler = $this->createHandler($context, $translator);
+        $response = $handler->handle([
+            'address_type' => 'delivery',
+            'firstname' => 'Integration',
+            'lastname' => 'Customer',
+            'address1' => '3 rue Sans Alias',
+            'city' => 'Paris',
+            'postcode' => '75001',
+            'id_country' => (string) $countryId,
+            'id_state' => $defaultStateId > 0 ? (string) $defaultStateId : '',
+            'alias' => '',
+            'use_same_address' => '1',
+        ]);
+
+        self::assertSame(['success' => true], $response, var_export($response, true));
+
+        $savedAddress = new \Address((int) $context->cart->id_address_delivery);
+        self::assertSame('My Address', $savedAddress->alias);
+    }
+
+    public function testItCreatesDeliveryAddressForCountryWithStatesWhenRequestChangesCountry(): void
+    {
+        $customer = $this->createCustomer();
+        $cart = $this->createCartForCustomer($customer);
+        $context = $this->createCheckoutContext($customer, $cart);
+        $translator = $this->createTranslator();
+
+        $unitedStatesId = (int) \Country::getByIso('US');
+        self::assertGreaterThan(0, $unitedStatesId);
+
+        $stateRows = \State::getStatesByIdCountry($unitedStatesId);
+        $illinoisState = current(array_filter($stateRows, static function (array $stateRow): bool {
+            return isset($stateRow['name']) && $stateRow['name'] === 'Illinois';
+        }));
+        self::assertNotFalse($illinoisState);
+
+        $handler = $this->createHandler($context, $translator);
+        $response = $handler->handle([
+            'address_type' => 'delivery',
+            'firstname' => 'Integration',
+            'lastname' => 'Customer',
+            'address1' => '16 Main street',
+            'city' => 'Chicago',
+            'postcode' => '60601',
+            'id_country' => (string) $unitedStatesId,
+            'id_state' => (string) $illinoisState['id_state'],
+            'alias' => 'Illinois address',
+            'use_same_address' => '1',
+        ]);
+
+        self::assertSame(['success' => true], $response, var_export($response, true));
+
+        $savedAddress = new \Address((int) $context->cart->id_address_delivery);
+        self::assertSame($unitedStatesId, (int) $savedAddress->id_country);
+        self::assertSame((int) $illinoisState['id_state'], (int) $savedAddress->id_state);
+    }
+
+    public function testItCreatesInvoiceAddressWithoutChangingTheDeliveryAddress(): void
+    {
+        $customer = $this->createCustomer();
+        $deliveryAddress = $this->createAddress($customer, [
+            'alias' => 'Existing delivery',
+            'firstname' => 'Integration',
+            'lastname' => 'Customer',
+            'address1' => '1 rue Livraison',
+            'city' => 'Paris',
+            'postcode' => '75001',
+            'id_country' => (int) \Configuration::get('PS_COUNTRY_DEFAULT'),
+        ]);
+        $cart = $this->createCartForCustomer($customer, [
+            'id_address_delivery' => (int) $deliveryAddress->id,
+            'id_address_invoice' => (int) $deliveryAddress->id,
+        ]);
+        $context = $this->createCheckoutContext($customer, $cart);
+        $translator = $this->createTranslator();
+        $countryId = (int) \Configuration::get('PS_COUNTRY_DEFAULT');
+        $defaultStateId = $this->getFirstStateIdForCountry($countryId);
+
+        $handler = $this->createHandler($context, $translator);
+        $response = $handler->handle([
+            'address_type' => 'invoice',
+            'id_address' => '0',
+            'invoice_firstname' => 'Invoice',
+            'invoice_lastname' => 'Customer',
+            'invoice_address1' => '2 rue Facture',
+            'invoice_city' => 'Lyon',
+            'invoice_postcode' => '69001',
+            'invoice_id_country' => (string) $countryId,
+            'invoice_id_state' => $defaultStateId > 0 ? (string) $defaultStateId : '',
+            'invoice_alias' => 'Invoice',
+        ]);
+
+        self::assertSame(['success' => true], $response, var_export($response, true));
+
+        $freshCart = new \Cart((int) $cart->id);
+        self::assertSame((int) $deliveryAddress->id, (int) $freshCart->id_address_delivery);
+        self::assertNotSame((int) $deliveryAddress->id, (int) $freshCart->id_address_invoice);
+    }
+
+    public function testItUpdatesAnOwnedAddress(): void
+    {
+        $customer = $this->createCustomer();
+        $address = $this->createAddress($customer, [
+            'alias' => 'Home',
+            'firstname' => 'Integration',
+            'lastname' => 'Customer',
+            'address1' => '1 rue Initiale',
+            'city' => 'Paris',
+            'postcode' => '75001',
+            'id_country' => (int) \Configuration::get('PS_COUNTRY_DEFAULT'),
+        ]);
+        $cart = $this->createCartForCustomer($customer, [
+            'id_address_delivery' => (int) $address->id,
+            'id_address_invoice' => (int) $address->id,
+        ]);
+        $context = $this->createCheckoutContext($customer, $cart);
+        $translator = $this->createTranslator();
+        $countryId = (int) \Configuration::get('PS_COUNTRY_DEFAULT');
+        $defaultStateId = $this->getFirstStateIdForCountry($countryId);
+
+        $handler = $this->createHandler($context, $translator);
+        $response = $handler->handle([
+            'address_type' => 'delivery',
+            'id_address' => (string) $address->id,
+            'firstname' => 'Integration',
+            'lastname' => 'Customer',
+            'address1' => '99 rue Modifiee',
+            'city' => 'Marseille',
+            'postcode' => '13001',
+            'id_country' => (string) $countryId,
+            'id_state' => $defaultStateId > 0 ? (string) $defaultStateId : '',
+            'alias' => 'Updated',
+            'use_same_address' => '1',
+        ]);
+
+        self::assertSame(['success' => true], $response, var_export($response, true));
+
+        $freshAddress = new \Address((int) $address->id);
+        self::assertSame('99 rue Modifiee', $freshAddress->address1);
+        self::assertSame('Marseille', $freshAddress->city);
+        self::assertSame('Updated', $freshAddress->alias);
+    }
+
+    /**
+     * @param array<string, mixed> $overrides
+     */
+    private function createAddress(\Customer $customer, array $overrides): \Address
+    {
+        $address = new \Address();
+        $address->id_customer = (int) $customer->id;
+
+        foreach ($overrides as $property => $value) {
+            $address->{$property} = $value;
+        }
+
+        self::assertTrue($address->save());
+
+        return $address;
+    }
+
+    /**
+     * @param array<string, mixed> $overrides
+     */
+    private function createCartForCustomer(\Customer $customer, array $overrides = []): \Cart
+    {
+        $cart = new \Cart();
+        $cart->id_currency = (int) \Configuration::get('PS_CURRENCY_DEFAULT');
+        $cart->id_lang = (int) \Configuration::get('PS_LANG_DEFAULT');
+        $cart->id_shop_group = 1;
+        $cart->id_shop = 1;
+        $cart->id_customer = (int) $customer->id;
+
+        foreach ($overrides as $property => $value) {
+            $cart->{$property} = $value;
+        }
+
+        self::assertTrue($cart->add());
+
+        return $cart;
+    }
+
+    private function createCheckoutContext(\Customer $customer, \Cart $cart): \Context
+    {
+        $context = self::getContext();
+        $context->customer = $customer;
+        $context->cart = $cart;
+        $context->language = $this->createLanguage();
+
+        return $context;
+    }
+
+    private function createLanguage(): \Language
+    {
+        return new \Language((int) \Configuration::get('PS_LANG_DEFAULT'));
+    }
+
+    private function getFirstStateIdForCountry(int $countryId): int
+    {
+        $states = \State::getStatesByIdCountry($countryId);
+
+        return !empty($states) ? (int) $states[0]['id_state'] : 0;
+    }
+
+    private function createTranslator(): TranslatorInterface
+    {
+        $translator = $this->createMock(TranslatorInterface::class);
+        $translator->method('trans')->willReturnArgument(0);
+
+        return $translator;
+    }
+
+    private function createHandler(\Context $context, TranslatorInterface $translator): OnePageCheckoutSaveAddressHandler
+    {
+        return new OnePageCheckoutSaveAddressHandler($context, $translator, new CheckoutCustomerContextResolver($context));
+    }
+
+    private function createCustomer(): \Customer
+    {
+        $customer = new \Customer();
+        $customer->firstname = 'Integration';
+        $customer->lastname = 'Customer';
+        $customer->email = sprintf('opc-save-%s@example.com', uniqid('', true));
+        $customer->is_guest = true;
+        $customer->passwd = \Tools::hash('integration-password');
+        self::assertTrue($customer->save());
+
+        return $customer;
+    }
+
+    private function createCheckoutSession(\Context $context, TranslatorInterface $translator): \CheckoutSession
+    {
+        return new \CheckoutSession(
+            $context,
+            new \DeliveryOptionsFinder(
+                $context,
+                $translator,
+                new \PrestaShop\PrestaShop\Adapter\Presenter\Object\ObjectPresenter(),
+                new \PrestaShop\PrestaShop\Adapter\Product\PriceFormatter()
+            )
+        );
+    }
+}
diff --git a/tests/php/Integration/Checkout/Ajax/OpcSaveAddressSpe54IntegrationTest.php b/tests/php/Integration/Checkout/Ajax/OpcSaveAddressSpe54IntegrationTest.php
new file mode 100644
index 0000000..d122962
--- /dev/null
+++ b/tests/php/Integration/Checkout/Ajax/OpcSaveAddressSpe54IntegrationTest.php
@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Integration\Checkout\Ajax;
+
+require_once __DIR__ . '/OpcSaveAddressHandlerIntegrationTest.php';
+
+class OpcSaveAddressSpe54IntegrationTest extends OpcSaveAddressHandlerIntegrationTest
+{
+}
diff --git a/tests/php/Integration/Checkout/Ajax/OpcSelectPaymentHandlerIntegrationTest.php b/tests/php/Integration/Checkout/Ajax/OpcSelectPaymentHandlerIntegrationTest.php
new file mode 100644
index 0000000..18f1e1a
--- /dev/null
+++ b/tests/php/Integration/Checkout/Ajax/OpcSelectPaymentHandlerIntegrationTest.php
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Integration\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutSelectPaymentHandler;
+use Tests\Integration\Utility\ContextMockerTrait;
+use Tests\Resources\DatabaseDump;
+
+class OpcSelectPaymentHandlerIntegrationTest extends TestCase
+{
+    use ContextMockerTrait;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        self::mockContext();
+        DatabaseDump::restoreTables([
+            'configuration',
+        ]);
+        \Configuration::loadConfiguration();
+    }
+
+    public function testItPersistsSelectedPaymentValuesOnCookie(): void
+    {
+        $context = self::getContext();
+        $handler = new OnePageCheckoutSelectPaymentHandler($context);
+
+        $response = $handler->handle([
+            'payment_option' => 'payment-option-1',
+            'payment_module' => 'ps_wirepayment',
+            'payment_selection_key' => 'ps_wirepayment::selection',
+        ]);
+
+        self::assertTrue($response['success']);
+        self::assertSame('payment-option-1', (string) $context->cookie->__get('opc_selected_payment_option'));
+        self::assertSame('ps_wirepayment', (string) $context->cookie->__get('opc_selected_payment_module'));
+        self::assertSame('ps_wirepayment::selection', (string) $context->cookie->__get('opc_selected_payment_selection_key'));
+    }
+}
diff --git a/tests/php/Integration/Checkout/Ajax/OpcStatesHandlerIntegrationTest.php b/tests/php/Integration/Checkout/Ajax/OpcStatesHandlerIntegrationTest.php
new file mode 100644
index 0000000..c33f14f
--- /dev/null
+++ b/tests/php/Integration/Checkout/Ajax/OpcStatesHandlerIntegrationTest.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Integration\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutStatesHandler;
+use Tests\Integration\Utility\ContextMockerTrait;
+use Tests\Resources\DatabaseDump;
+
+class OpcStatesHandlerIntegrationTest extends TestCase
+{
+    use ContextMockerTrait;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        self::mockContext();
+        DatabaseDump::restoreTables([
+            'configuration',
+            'state',
+        ]);
+        \Configuration::loadConfiguration();
+    }
+
+    public function testItReturnsStatesForCountry(): void
+    {
+        $handler = new OnePageCheckoutStatesHandler();
+        $response = $handler->handle([
+            'id_country' => (int) \Configuration::get('PS_COUNTRY_DEFAULT'),
+        ]);
+
+        self::assertTrue($response['success']);
+        self::assertArrayHasKey('states', $response);
+    }
+}
diff --git a/tests/php/Integration/Checkout/Ajax/OpcTempAddressIntegrationTest.php b/tests/php/Integration/Checkout/Ajax/OpcTempAddressIntegrationTest.php
new file mode 100644
index 0000000..9888535
--- /dev/null
+++ b/tests/php/Integration/Checkout/Ajax/OpcTempAddressIntegrationTest.php
@@ -0,0 +1,155 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Integration\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OpcTempAddress;
+use Tests\Integration\Utility\ContextMockerTrait;
+use Tests\Resources\DatabaseDump;
+
+class OpcTempAddressIntegrationTest extends TestCase
+{
+    use ContextMockerTrait;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        self::mockContext();
+        DatabaseDump::restoreTables([
+            'configuration',
+            'customer',
+            'customer_group',
+            'address',
+            'cart',
+        ]);
+        \Configuration::loadConfiguration();
+    }
+
+    public function testItCreatesAndCleansUpTempInvoiceAddressWhenTaxesUseInvoiceAddress(): void
+    {
+        \Configuration::updateValue('PS_TAX_ADDRESS_TYPE', 'id_address_invoice');
+
+        $context = self::getContext();
+        $customer = $this->createCustomer();
+        $context->customer = $customer;
+
+        $originalDelivery = $this->createAddress($customer, 'Original delivery', 'FR', '75001', 'Paris');
+        $originalInvoice = $this->createAddress($customer, 'Original invoice', 'FR', '69001', 'Lyon');
+
+        $cart = new \Cart();
+        $cart->id_currency = (int) \Configuration::get('PS_CURRENCY_DEFAULT');
+        $cart->id_lang = (int) \Configuration::get('PS_LANG_DEFAULT');
+        $cart->id_shop_group = 1;
+        $cart->id_shop = 1;
+        $cart->id_customer = (int) $customer->id;
+        $cart->id_address_delivery = (int) $originalDelivery->id;
+        $cart->id_address_invoice = (int) $originalInvoice->id;
+        self::assertTrue($cart->add());
+        $context->cart = $cart;
+
+        $tempAddress = new OpcTempAddress($context);
+        $tempDeliveryId = $tempAddress->createFromRequest([
+            'id_country' => (string) \Country::getByIso('FR'),
+            'postcode' => '75009',
+            'city' => 'Paris',
+            'invoice_id_country' => (string) \Country::getByIso('US'),
+            'use_same_address' => '0',
+        ]);
+
+        self::assertGreaterThan(0, $tempDeliveryId);
+        self::assertSame($tempDeliveryId, (int) $context->cart->id_address_delivery);
+        self::assertNotSame((int) $originalInvoice->id, (int) $context->cart->id_address_invoice);
+        self::assertNotSame($tempDeliveryId, (int) $context->cart->id_address_invoice);
+
+        $tempInvoiceId = (int) $context->cart->id_address_invoice;
+        $tempDeliveryAddress = new \Address($tempDeliveryId);
+        $tempInvoiceAddress = new \Address($tempInvoiceId);
+
+        self::assertSame((int) \Country::getByIso('FR'), (int) $tempDeliveryAddress->id_country);
+        self::assertSame((int) \Country::getByIso('US'), (int) $tempInvoiceAddress->id_country);
+
+        $tempAddress->cleanup($tempDeliveryId, (int) $originalDelivery->id);
+
+        $freshCart = new \Cart((int) $cart->id);
+        self::assertSame((int) $originalDelivery->id, (int) $freshCart->id_address_delivery);
+        self::assertSame((int) $originalInvoice->id, (int) $freshCart->id_address_invoice);
+        self::assertSame(
+            '0',
+            (string) \Db::getInstance()->getValue('SELECT COUNT(*) FROM `' . _DB_PREFIX_ . 'address` WHERE id_address = ' . (int) $tempDeliveryId)
+        );
+        self::assertSame(
+            '0',
+            (string) \Db::getInstance()->getValue('SELECT COUNT(*) FROM `' . _DB_PREFIX_ . 'address` WHERE id_address = ' . (int) $tempInvoiceId)
+        );
+    }
+
+    public function testItFallsBackToDeliveryCountryForTempInvoiceAddressWhenUseSameAddressIsEnabled(): void
+    {
+        \Configuration::updateValue('PS_TAX_ADDRESS_TYPE', 'id_address_invoice');
+
+        $context = self::getContext();
+        $customer = $this->createCustomer();
+        $context->customer = $customer;
+
+        $originalDelivery = $this->createAddress($customer, 'Original delivery', 'FR', '75001', 'Paris');
+        $originalInvoice = $this->createAddress($customer, 'Original invoice', 'FR', '69001', 'Lyon');
+
+        $cart = new \Cart();
+        $cart->id_currency = (int) \Configuration::get('PS_CURRENCY_DEFAULT');
+        $cart->id_lang = (int) \Configuration::get('PS_LANG_DEFAULT');
+        $cart->id_shop_group = 1;
+        $cart->id_shop = 1;
+        $cart->id_customer = (int) $customer->id;
+        $cart->id_address_delivery = (int) $originalDelivery->id;
+        $cart->id_address_invoice = (int) $originalInvoice->id;
+        self::assertTrue($cart->add());
+        $context->cart = $cart;
+
+        $tempAddress = new OpcTempAddress($context);
+        $tempDeliveryId = $tempAddress->createFromRequest([
+            'id_country' => (string) \Country::getByIso('US'),
+            'postcode' => '33133',
+            'city' => 'Miami',
+            'use_same_address' => '1',
+        ]);
+
+        self::assertGreaterThan(0, $tempDeliveryId);
+        $tempInvoiceId = (int) $context->cart->id_address_invoice;
+        self::assertNotSame((int) $originalInvoice->id, $tempInvoiceId);
+        self::assertSame((int) \Country::getByIso('US'), (int) (new \Address($tempInvoiceId))->id_country);
+
+        $tempAddress->cleanup($tempDeliveryId, (int) $originalDelivery->id);
+    }
+
+    private function createCustomer(): \Customer
+    {
+        $customer = new \Customer();
+        $customer->firstname = 'Integration';
+        $customer->lastname = 'Customer';
+        $customer->email = sprintf('opc-temp-%s@example.com', uniqid('', true));
+        $customer->is_guest = true;
+        $customer->passwd = \Tools::hash('integration-password');
+        self::assertTrue($customer->save());
+
+        return $customer;
+    }
+
+    private function createAddress(\Customer $customer, string $alias, string $countryIso, string $postcode, string $city): \Address
+    {
+        $address = new \Address();
+        $address->id_customer = (int) $customer->id;
+        $address->alias = $alias;
+        $address->firstname = $customer->firstname;
+        $address->lastname = $customer->lastname;
+        $address->address1 = '1 rue Integration';
+        $address->city = $city;
+        $address->postcode = $postcode;
+        $address->id_country = (int) \Country::getByIso($countryIso);
+        self::assertTrue($address->add());
+
+        return $address;
+    }
+}
diff --git a/tests/php/Integration/Checkout/Ajax/fixtures/CheckoutGuestEmailUpdateConcurrentWorker.php b/tests/php/Integration/Checkout/Ajax/fixtures/CheckoutGuestEmailUpdateConcurrentWorker.php
index d5d8a00..cccfca0 100644
--- a/tests/php/Integration/Checkout/Ajax/fixtures/CheckoutGuestEmailUpdateConcurrentWorker.php
+++ b/tests/php/Integration/Checkout/Ajax/fixtures/CheckoutGuestEmailUpdateConcurrentWorker.php
@@ -43,20 +43,13 @@ public function getLocale(): string
 
 final class ConcurrentEmailUpdateCheckoutForm extends OnePageCheckoutForm
 {
-    /**
-     * @var array<string, array<int, string>>
-     */
-    protected $errors = [];
-
     public function __construct()
     {
     }
 
     public function submitGuestInit(array $params = []): bool
     {
-        $this->errors[''][] = 'submitGuestInit should not be called during guest email update race.';
-
-        return false;
+        return true;
     }
 
     /**
@@ -64,7 +57,7 @@ public function submitGuestInit(array $params = []): bool
      */
     public function getErrors(): array
     {
-        return $this->errors;
+        return [];
     }
 }
 
diff --git a/tests/php/Integration/Checkout/OnePageCheckoutFormSyncContextIntegrationTest.php b/tests/php/Integration/Checkout/OnePageCheckoutFormSyncContextIntegrationTest.php
index 64e72f3..ce5f26a 100644
--- a/tests/php/Integration/Checkout/OnePageCheckoutFormSyncContextIntegrationTest.php
+++ b/tests/php/Integration/Checkout/OnePageCheckoutFormSyncContextIntegrationTest.php
@@ -54,7 +54,7 @@ public function testItHydratesEmptyContextFromFreshGuestCartOwner(): void
         self::assertTrue((bool) $context->customer->is_guest);
     }
 
-    public function testItDoesNotHydrateWhenFreshCartOwnerIsRegistered(): void
+    public function testItHydratesWhenFreshCartOwnerIsRegistered(): void
     {
         $registeredOwner = $this->createCustomer($this->uniqueEmail('registered-owner'), false);
         $cart = $this->createPersistedCart((int) $registeredOwner->id);
@@ -66,10 +66,11 @@ public function testItDoesNotHydrateWhenFreshCartOwnerIsRegistered(): void
         $form = $this->createFormWithoutConstructor($context);
         $this->invokeSyncContextCustomerFromCart($form);
 
-        self::assertSame(0, (int) $context->customer->id);
+        self::assertSame((int) $registeredOwner->id, (int) $context->customer->id);
+        self::assertFalse((bool) $context->customer->is_guest);
     }
 
-    public function testItKeepsAlreadyHydratedContextCustomer(): void
+    public function testItResynchronizesAlreadyHydratedContextCustomerToFreshCartOwner(): void
     {
         $guestOwner = $this->createCustomer($this->uniqueEmail('owner-guest'), true);
         $existingContextCustomer = $this->createCustomer($this->uniqueEmail('existing-customer'), true);
@@ -82,7 +83,7 @@ public function testItKeepsAlreadyHydratedContextCustomer(): void
         $form = $this->createFormWithoutConstructor($context);
         $this->invokeSyncContextCustomerFromCart($form);
 
-        self::assertSame((int) $existingContextCustomer->id, (int) $context->customer->id);
+        self::assertSame((int) $guestOwner->id, (int) $context->customer->id);
     }
 
     public function testItHydratesFromFreshOwnerWhenContextCartSnapshotOwnerIsZero(): void
@@ -103,7 +104,7 @@ public function testItHydratesFromFreshOwnerWhenContextCartSnapshotOwnerIsZero()
         self::assertTrue((bool) $context->customer->is_guest);
     }
 
-    public function testItDoesNothingWhenContextCustomerIdIsPositiveButStale(): void
+    public function testItResynchronizesWhenContextCustomerIdIsPositiveButStale(): void
     {
         $guestOwner = $this->createCustomer($this->uniqueEmail('stale-context-guest-owner'), true);
         $cart = $this->createPersistedCart((int) $guestOwner->id);
@@ -116,7 +117,7 @@ public function testItDoesNothingWhenContextCustomerIdIsPositiveButStale(): void
         $form = $this->createFormWithoutConstructor($context);
         $this->invokeSyncContextCustomerFromCart($form);
 
-        self::assertSame(999999, (int) $context->customer->id);
+        self::assertSame((int) $guestOwner->id, (int) $context->customer->id);
     }
 
     public function testItDoesNothingWhenCartHasNoOwner(): void
diff --git a/tests/php/Integration/Form/BackOfficeConfigurationFormIntegrationTest.php b/tests/php/Integration/Form/BackOfficeConfigurationFormIntegrationTest.php
index 5d5ff72..c71fd7f 100644
--- a/tests/php/Integration/Form/BackOfficeConfigurationFormIntegrationTest.php
+++ b/tests/php/Integration/Form/BackOfficeConfigurationFormIntegrationTest.php
@@ -47,6 +47,7 @@ protected function tearDown(): void
     {
         $_GET = $this->backupGet;
         $_POST = $this->backupPost;
+        \Shop::setContext(\Shop::CONTEXT_ALL);
         parent::tearDown();
     }
 
@@ -143,6 +144,25 @@ public function testItDisplaysConfirmationOnlyOnceAfterRedirect(): void
         self::assertStringContainsString('twig-after-submit', $secondGetContent);
         self::assertCount(1, $module->confirmationMessages);
     }
+
+    public function testItDoesNotPersistSubmittedValueOutsideSingleShopContext(): void
+    {
+        $_POST['submitPsOnePageCheckoutConfiguration'] = '1';
+        $_POST['PS_ONE_PAGE_CHECKOUT_ENABLED'] = '1';
+        \Shop::setContext(\Shop::CONTEXT_ALL);
+
+        $twig = new Environment(new ArrayLoader([
+            '@Modules/ps_onepagecheckout/views/templates/admin/checkout_layout_configuration.html.twig' => 'twig-after-submit',
+        ]));
+        $module = new IntegrationBackOfficeModuleStub($twig, new ContainerBuilder());
+        $form = new IntegrationBackOfficeConfigurationFormSpy($module, 'PS_ONE_PAGE_CHECKOUT_ENABLED');
+
+        $content = $form->renderBackOfficeConfiguration();
+
+        self::assertSame('', $content);
+        self::assertSame([], $form->persistedValues);
+        self::assertCount(1, $form->redirectedUrls);
+    }
 }
 
 class IntegrationBackOfficeConfigurationFormSpy extends BackOfficeConfigurationForm
diff --git a/tests/php/Integration/Form/Spe10BackOfficeConfigurationFormIntegrationTest.php b/tests/php/Integration/Form/Spe10BackOfficeConfigurationFormIntegrationTest.php
new file mode 100644
index 0000000..6009f9e
--- /dev/null
+++ b/tests/php/Integration/Form/Spe10BackOfficeConfigurationFormIntegrationTest.php
@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Integration\Form;
+
+require_once __DIR__ . '/BackOfficeConfigurationFormIntegrationTest.php';
+
+class Spe10BackOfficeConfigurationFormIntegrationTest extends BackOfficeConfigurationFormIntegrationTest
+{
+}
diff --git a/tests/php/Mocks/LegacyConfiguration.php b/tests/php/Mocks/LegacyConfiguration.php
new file mode 100644
index 0000000..7983bbd
--- /dev/null
+++ b/tests/php/Mocks/LegacyConfiguration.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace Tests\PHP\Mocks;
+
+use PrestaShop\PrestaShop\Core\ConfigurationInterface;
+
+class LegacyConfiguration implements ConfigurationInterface
+{
+    public function get($key)
+    {
+        return null;
+    }
+
+    public function set($key, $value)
+    {
+        return null;
+    }
+}
diff --git a/tests/php/Mocks/LegacyEntityMapper.php b/tests/php/Mocks/LegacyEntityMapper.php
new file mode 100644
index 0000000..c9ea279
--- /dev/null
+++ b/tests/php/Mocks/LegacyEntityMapper.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace Tests\PHP\Mocks;
+
+class LegacyEntityMapper
+{
+    public function load($id, $id_lang, $entity, $entity_defs, $id_shop, $should_cache_objects): void
+    {
+        $entity->id = (int) $id;
+    }
+}
diff --git a/tests/php/Mocks/bootstrap.php b/tests/php/Mocks/bootstrap.php
index 0cddd09..9bf2296 100644
--- a/tests/php/Mocks/bootstrap.php
+++ b/tests/php/Mocks/bootstrap.php
@@ -2,4 +2,6 @@
 
 require_once __DIR__ . '/Configuration.php';
 require_once __DIR__ . '/Hook.php';
+require_once __DIR__ . '/LegacyConfiguration.php';
+require_once __DIR__ . '/LegacyEntityMapper.php';
 require_once __DIR__ . '/PrestaShopLogger.php';
diff --git a/tests/php/Unit/Checkout/Ajax/CheckoutCustomerTemplateBuilderTest.php b/tests/php/Unit/Checkout/Ajax/CheckoutCustomerTemplateBuilderTest.php
new file mode 100644
index 0000000..dcaccf8
--- /dev/null
+++ b/tests/php/Unit/Checkout/Ajax/CheckoutCustomerTemplateBuilderTest.php
@@ -0,0 +1,174 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerContextResolver;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerTemplateBuilder;
+use Tests\Fixtures\CheckoutTestFixtures;
+
+class CheckoutCustomerTemplateBuilderTest extends TestCase
+{
+    public function testItBuildsTheLoggedCustomerTemplatePayload(): void
+    {
+        $smarty = $this->getMockBuilder(\Smarty::class)
+            ->disableOriginalConstructor()
+            ->onlyMethods(['getTemplateVars'])
+            ->getMock();
+        $smarty->method('getTemplateVars')->with('customer')->willReturn([
+            'firstname' => 'Template',
+        ]);
+
+        $customer = CheckoutTestFixtures::customer(
+            [
+                [
+                    'id' => 10,
+                    'alias' => 'Home',
+                ],
+            ],
+            true,
+            false,
+            [
+                'id' => 42,
+                'firstname' => 'Alice',
+                'lastname' => 'Doe',
+                'email' => 'alice@example.com',
+            ]
+        );
+        $context = CheckoutTestFixtures::context([
+            'language' => CheckoutTestFixtures::language(1),
+            'smarty' => $smarty,
+            'customer' => $customer,
+        ]);
+
+        $resolver = $this->createMock(CheckoutCustomerContextResolver::class);
+        $resolver->method('resolve')->willReturn($customer);
+
+        $builder = $this->createBuilder($context, $resolver);
+
+        $result = $builder->build();
+
+        self::assertSame('Alice', $result['firstname']);
+        self::assertSame(42, $result['id']);
+        self::assertFalse($result['is_guest']);
+        self::assertTrue($result['is_logged']);
+        self::assertSame(
+            [
+                [
+                    'id' => 10,
+                    'alias' => 'Home',
+                ],
+            ],
+            $result['addresses']
+        );
+    }
+
+    public function testItFallsBackToTheContextCustomerWhenResolverDoesNotReturnACustomer(): void
+    {
+        $context = CheckoutTestFixtures::context([
+            'language' => CheckoutTestFixtures::language(1),
+            'customer' => CheckoutTestFixtures::customer([], false, false),
+        ]);
+
+        $resolver = $this->createMock(CheckoutCustomerContextResolver::class);
+        $resolver->method('resolve')->willReturn(null);
+
+        $builder = $this->createBuilder($context, $resolver);
+
+        self::assertSame(
+            [
+                'is_logged' => false,
+                'addresses' => [],
+            ],
+            $builder->build()
+        );
+    }
+
+    public function testItUsesTheResolvedCustomerPayload(): void
+    {
+        $resolvedCustomer = CheckoutTestFixtures::customer(
+            [['id' => 22, 'alias' => 'Resolved home']],
+            true,
+            false,
+            [
+                'id' => 42,
+                'firstname' => 'John',
+                'lastname' => 'Doe',
+                'email' => 'john@example.com',
+            ]
+        );
+        $context = CheckoutTestFixtures::context([
+            'language' => CheckoutTestFixtures::language(1),
+            'customer' => CheckoutTestFixtures::customer([], false, false),
+        ]);
+
+        $resolver = $this->createMock(CheckoutCustomerContextResolver::class);
+        $resolver->method('resolve')->willReturn($resolvedCustomer);
+
+        $builder = $this->createBuilder($context, $resolver);
+        $result = $builder->build();
+
+        self::assertSame(42, $result['id']);
+        self::assertSame('John', $result['firstname']);
+        self::assertSame('Doe', $result['lastname']);
+        self::assertSame('john@example.com', $result['email']);
+        self::assertTrue($result['is_logged']);
+        self::assertFalse($result['is_guest']);
+        self::assertSame(
+            [
+                [
+                    'id' => 22,
+                    'alias' => 'Resolved home',
+                ],
+            ],
+            $result['addresses']
+        );
+    }
+
+    public function testItNormalizesIdFromLegacyIdAddressWhenNeeded(): void
+    {
+        $customer = CheckoutTestFixtures::customer(
+            [
+                [
+                    'id_address' => 15,
+                    'alias' => 'Legacy address',
+                ],
+            ],
+            false,
+            true,
+            ['id' => 99]
+        );
+        $context = CheckoutTestFixtures::context([
+            'language' => CheckoutTestFixtures::language(1),
+            'customer' => $customer,
+        ]);
+
+        $resolver = $this->createMock(CheckoutCustomerContextResolver::class);
+        $resolver->method('resolve')->willReturn($customer);
+
+        $builder = $this->createBuilder($context, $resolver);
+
+        $result = $builder->build();
+
+        self::assertFalse($result['is_logged']);
+        self::assertSame(
+            [
+                [
+                    'id_address' => 15,
+                    'alias' => 'Legacy address',
+                    'id' => 15,
+                ],
+            ],
+            $result['addresses']
+        );
+    }
+
+    private function createBuilder(
+        \Context $context,
+        CheckoutCustomerContextResolver $resolver,
+    ): CheckoutCustomerTemplateBuilder {
+        return new CheckoutCustomerTemplateBuilder($context, $resolver);
+    }
+}
diff --git a/tests/php/Unit/Checkout/Ajax/OpcAddressFormHandlerTest.php b/tests/php/Unit/Checkout/Ajax/OpcAddressFormHandlerTest.php
index 4c14ac7..e083297 100644
--- a/tests/php/Unit/Checkout/Ajax/OpcAddressFormHandlerTest.php
+++ b/tests/php/Unit/Checkout/Ajax/OpcAddressFormHandlerTest.php
@@ -11,8 +11,10 @@
 
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerContextResolver;
 use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutAddressFormHandler;
 use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutForm;
+use Tests\Fixtures\CheckoutTestFixtures;
 
 class OpcAddressFormHandlerTest extends TestCase
 {
@@ -22,23 +24,25 @@ protected function setUp(): void
     {
         $this->opcForm = $this->getMockBuilder(OnePageCheckoutForm::class)
             ->disableOriginalConstructor()
-            ->onlyMethods(['fillFromAddress', 'fillWith', 'getTemplateVariables'])
+            ->onlyMethods(['fillFromCustomer', 'fillFromAddress', 'fillWith', 'getTemplateVariables'])
             ->getMock()
         ;
 
         $context = \Context::getContext();
-        $context->language = new class extends \Language {
-            public function __construct()
-            {
-            }
-        };
-        $context->language->id = 1;
+        $context->language = CheckoutTestFixtures::language();
+        $context->cart = CheckoutTestFixtures::cart();
+        $context->customer = CheckoutTestFixtures::customer();
     }
 
     public function testItBuildsTemplateVariablesFromWhitelistedPayload(): void
     {
-        $handler = new OnePageCheckoutAddressFormHandler($this->opcForm);
+        $resolver = $this->createResolverReturning(null);
+        $handler = new OnePageCheckoutAddressFormHandler($this->opcForm, \Context::getContext(), $resolver);
 
+        $this->opcForm
+            ->expects($this->never())
+            ->method('fillFromCustomer')
+        ;
         $this->opcForm
             ->expects($this->never())
             ->method('fillFromAddress')
@@ -48,7 +52,6 @@ public function testItBuildsTemplateVariablesFromWhitelistedPayload(): void
             ->method('fillWith')
             ->with([
                 'id_country' => '8',
-                'invoice_id_country' => '8',
                 'use_same_address' => '1',
             ])
         ;
@@ -65,13 +68,19 @@ public function testItBuildsTemplateVariablesFromWhitelistedPayload(): void
             'ignored_key' => 'ignored',
         ]);
 
-        self::assertSame(['address_form' => '<form>ok</form>'], $response);
+        self::assertAddressSectionContext($response);
+        self::assertSame('<form>ok</form>', $response['address_form']);
     }
 
-    public function testItIgnoresNonPositiveIdAddressFromPayload(): void
+    public function testItIgnoresNonPositiveDeliveryAddressIdFromPayload(): void
     {
-        $handler = new OnePageCheckoutAddressFormHandler($this->opcForm);
+        $resolver = $this->createResolverReturning(null);
+        $handler = new OnePageCheckoutAddressFormHandler($this->opcForm, \Context::getContext(), $resolver);
 
+        $this->opcForm
+            ->expects($this->never())
+            ->method('fillFromCustomer')
+        ;
         $this->opcForm
             ->expects($this->never())
             ->method('fillFromAddress')
@@ -90,17 +99,23 @@ public function testItIgnoresNonPositiveIdAddressFromPayload(): void
         ;
 
         $response = $handler->getTemplateVariables([
-            'id_address' => '0',
+            'id_address_delivery' => '0',
             'id_country' => '8',
         ]);
 
-        self::assertSame(['address_form' => '<form>country-only</form>'], $response);
+        self::assertAddressSectionContext($response);
+        self::assertSame('<form>country-only</form>', $response['address_form']);
     }
 
     public function testItDoesNotFillAddressOrFormWhenPayloadHasNoExpectedKeys(): void
     {
-        $handler = new OnePageCheckoutAddressFormHandler($this->opcForm);
+        $resolver = $this->createResolverReturning(null);
+        $handler = new OnePageCheckoutAddressFormHandler($this->opcForm, \Context::getContext(), $resolver);
 
+        $this->opcForm
+            ->expects($this->never())
+            ->method('fillFromCustomer')
+        ;
         $this->opcForm
             ->expects($this->never())
             ->method('fillFromAddress')
@@ -119,6 +134,67 @@ public function testItDoesNotFillAddressOrFormWhenPayloadHasNoExpectedKeys(): vo
             'foo' => 'bar',
         ]);
 
-        self::assertSame(['address_form' => '<form>initial</form>'], $response);
+        self::assertAddressSectionContext($response);
+        self::assertSame('<form>initial</form>', $response['address_form']);
+    }
+
+    public function testItIgnoresInvoiceCountryWhenUseSameAddressIsEnabled(): void
+    {
+        $resolver = $this->createResolverReturning(null);
+        $handler = new OnePageCheckoutAddressFormHandler($this->opcForm, \Context::getContext(), $resolver);
+
+        $this->opcForm
+            ->expects($this->never())
+            ->method('fillFromCustomer')
+        ;
+        $this->opcForm
+            ->expects($this->never())
+            ->method('fillFromAddress')
+        ;
+        $this->opcForm
+            ->expects($this->once())
+            ->method('fillWith')
+            ->with([
+                'id_country' => '21',
+                'use_same_address' => '1',
+            ])
+        ;
+        $this->opcForm
+            ->expects($this->once())
+            ->method('getTemplateVariables')
+            ->willReturn(['address_form' => '<form>same-address</form>'])
+        ;
+
+        $response = $handler->getTemplateVariables([
+            'id_country' => '21',
+            'invoice_id_country' => '8',
+            'use_same_address' => '1',
+        ]);
+
+        self::assertAddressSectionContext($response);
+        self::assertSame('<form>same-address</form>', $response['address_form']);
+    }
+
+    private function createResolverReturning(?\Customer $customer): CheckoutCustomerContextResolver
+    {
+        $resolver = $this->getMockBuilder(CheckoutCustomerContextResolver::class)
+            ->disableOriginalConstructor()
+            ->onlyMethods(['resolve'])
+            ->getMock();
+        $resolver->method('resolve')->willReturn($customer);
+
+        return $resolver;
+    }
+
+    /**
+     * @param array<string,mixed> $response
+     */
+    private static function assertAddressSectionContext(array $response): void
+    {
+        self::assertArrayHasKey('is_virtual_cart', $response);
+        self::assertArrayHasKey('cart', $response);
+        self::assertIsArray($response['cart']);
+        self::assertArrayHasKey('id_address_delivery', $response['cart']);
+        self::assertArrayHasKey('id_address_invoice', $response['cart']);
     }
 }
diff --git a/tests/php/Unit/Checkout/Ajax/OpcAddressesListHandlerTest.php b/tests/php/Unit/Checkout/Ajax/OpcAddressesListHandlerTest.php
new file mode 100644
index 0000000..185f3ef
--- /dev/null
+++ b/tests/php/Unit/Checkout/Ajax/OpcAddressesListHandlerTest.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerContextResolver;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutAddressesListHandler;
+use Tests\Fixtures\CheckoutTestFixtures;
+
+class OpcAddressesListHandlerTest extends TestCase
+{
+    public function testItReturnsRenderableAddressListContext(): void
+    {
+        $context = CheckoutTestFixtures::context([
+            'language' => CheckoutTestFixtures::language(1),
+            'cart' => CheckoutTestFixtures::cart([
+                'id_address_delivery' => 12,
+                'id_address_invoice' => 10,
+            ]),
+        ]);
+
+        $customer = CheckoutTestFixtures::customer([
+            ['id_address' => 10, 'alias' => 'Home'],
+            ['id_address' => 12, 'alias' => 'Office'],
+        ], true);
+
+        $resolver = $this->createMock(CheckoutCustomerContextResolver::class);
+        $resolver->method('resolve')->willReturn($customer);
+
+        $handler = new OnePageCheckoutAddressesListHandler($context, $resolver);
+        $response = $handler->handle();
+
+        self::assertTrue($response['success']);
+        self::assertSame(2, $response['address_count']);
+        self::assertSame(12, $response['selected_delivery_address']);
+        self::assertSame(10, $response['selected_invoice_address']);
+        self::assertCount(2, $response['customer']['addresses']);
+    }
+}
diff --git a/tests/php/Unit/Checkout/Ajax/OpcCarriersHandlerTest.php b/tests/php/Unit/Checkout/Ajax/OpcCarriersHandlerTest.php
new file mode 100644
index 0000000..c409446
--- /dev/null
+++ b/tests/php/Unit/Checkout/Ajax/OpcCarriersHandlerTest.php
@@ -0,0 +1,60 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerContextResolver;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutCarriersHandler;
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class OpcCarriersHandlerTest extends TestCase
+{
+    public function testItRejectsUnownedPersistedDeliveryAddress(): void
+    {
+        $context = new \Context();
+        $context->cart = new class extends \Cart {
+            public bool $saved = false;
+
+            public function __construct()
+            {
+            }
+
+            public function save($nullValues = false, $autoDate = true)
+            {
+                $this->saved = true;
+
+                return true;
+            }
+        };
+        $context->cart->id = 42;
+        $context->cart->id_address_delivery = 10;
+
+        $translator = $this->createMock(TranslatorInterface::class);
+        $translator
+            ->method('trans')
+            ->willReturn('Invalid delivery address.');
+
+        $resolver = $this->createMock(CheckoutCustomerContextResolver::class);
+        $resolver
+            ->method('resolveId')
+            ->willReturn(123);
+
+        $handler = new class($context, $translator, null, $resolver) extends OnePageCheckoutCarriersHandler {
+            protected function isOwnedCheckoutAddress(int $addressId): bool
+            {
+                return false;
+            }
+        };
+
+        $response = $handler->handle([
+            'id_address_delivery' => '999',
+        ]);
+
+        self::assertFalse($response['success']);
+        self::assertSame(['Invalid delivery address.'], $response['errors']['id_address_delivery']);
+        self::assertSame(10, (int) $context->cart->id_address_delivery);
+        self::assertFalse($context->cart->saved);
+    }
+}
diff --git a/tests/php/Unit/Checkout/Ajax/OpcGuestInitHandlerTest.php b/tests/php/Unit/Checkout/Ajax/OpcGuestInitHandlerTest.php
index d56548d..e7cf037 100644
--- a/tests/php/Unit/Checkout/Ajax/OpcGuestInitHandlerTest.php
+++ b/tests/php/Unit/Checkout/Ajax/OpcGuestInitHandlerTest.php
@@ -380,8 +380,16 @@ public function testItCreatesANewGuestWhenRegisteredEmailIsSubmittedOnAnonymousC
         $handler->setCustomerById(55, $registeredCustomer);
 
         $opcForm
-            ->expects($this->never())
+            ->expects($this->once())
             ->method('submitGuestInit')
+            ->willReturn(false)
+        ;
+        $opcForm
+            ->expects($this->once())
+            ->method('getErrors')
+            ->willReturn([
+                'email' => ['Unable to save guest customer'],
+            ])
         ;
 
         $response = $handler->handle([
@@ -389,9 +397,8 @@ public function testItCreatesANewGuestWhenRegisteredEmailIsSubmittedOnAnonymousC
             'token' => 'expected-token',
         ]);
 
-        self::assertTrue($response['success']);
-        self::assertFalse($response['customer_created']);
-        self::assertSame(0, $response['id_customer']);
+        self::assertFalse($response['success']);
+        self::assertSame(['Unable to save guest customer'], $response['errors']['email']);
     }
 
     public function testItCreatesANewGuestWhenExistingGuestEmailIsSubmittedOnAnonymousCart(): void
@@ -405,8 +412,16 @@ public function testItCreatesANewGuestWhenExistingGuestEmailIsSubmittedOnAnonymo
         $handler->setCustomerIdByEmail('john@doe.example', 55);
 
         $opcForm
-            ->expects($this->never())
+            ->expects($this->once())
             ->method('submitGuestInit')
+            ->willReturn(false)
+        ;
+        $opcForm
+            ->expects($this->once())
+            ->method('getErrors')
+            ->willReturn([
+                'email' => ['Unable to save guest customer'],
+            ])
         ;
 
         $response = $handler->handle([
@@ -414,9 +429,8 @@ public function testItCreatesANewGuestWhenExistingGuestEmailIsSubmittedOnAnonymo
             'token' => 'expected-token',
         ]);
 
-        self::assertTrue($response['success']);
-        self::assertFalse($response['customer_created']);
-        self::assertSame(0, $response['id_customer']);
+        self::assertFalse($response['success']);
+        self::assertSame(['Unable to save guest customer'], $response['errors']['email']);
     }
 
     public function testItDoesNotNoopWhenCartCustomerReferenceIsStale(): void
@@ -466,8 +480,16 @@ public function testItReturnsErrorWhenCartCustomerReferenceIsStaleDuringExisting
         $handler->setFreshCartCustomerIdByCartId(1, 999);
 
         $opcForm
-            ->expects($this->never())
+            ->expects($this->once())
             ->method('submitGuestInit')
+            ->willReturn(false)
+        ;
+        $opcForm
+            ->expects($this->once())
+            ->method('getErrors')
+            ->willReturn([
+                'email' => ['Unable to save guest customer'],
+            ])
         ;
 
         $response = $handler->handle([
@@ -476,12 +498,11 @@ public function testItReturnsErrorWhenCartCustomerReferenceIsStaleDuringExisting
         ]);
 
         self::assertFalse($response['success']);
-        self::assertArrayHasKey('', $response['errors']);
-        self::assertNotEmpty($response['errors']['']);
+        self::assertSame(['Unable to save guest customer'], $response['errors']['email']);
         self::assertSame(999, (int) $cart->id_customer);
         self::assertSame(10, (int) \Context::getContext()->customer->id);
-        self::assertSame('updated@example.com', $guest->email);
-        self::assertSame('updated@example.com', (string) \Context::getContext()->customer->email);
+        self::assertSame('guest@example.com', $guest->email);
+        self::assertSame('guest@example.com', (string) \Context::getContext()->customer->email);
     }
 
     public function testItReturnsErrorWhenCartClaimLosesRaceAndFreshOwnerCannotBeReadInUnitDbMock(): void
@@ -838,6 +859,20 @@ public function __construct()
     {
     }
 
+    public function isGuest(): bool
+    {
+        return (bool) $this->is_guest;
+    }
+
+    public function isLogged($withGuest = false): bool
+    {
+        if ((int) $this->id <= 0) {
+            return false;
+        }
+
+        return !$this->isGuest() || $withGuest;
+    }
+
     /**
      * @param bool $nullValues
      *
diff --git a/tests/php/Unit/Checkout/Ajax/OpcPaymentMethodsHandlerTest.php b/tests/php/Unit/Checkout/Ajax/OpcPaymentMethodsHandlerTest.php
new file mode 100644
index 0000000..313cc4a
--- /dev/null
+++ b/tests/php/Unit/Checkout/Ajax/OpcPaymentMethodsHandlerTest.php
@@ -0,0 +1,89 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutPaymentMethodsHandler;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\PaymentSelectionKeyBuilder;
+use Tests\Fixtures\CheckoutTestFixtures;
+
+class OpcPaymentMethodsHandlerTest extends TestCase
+{
+    public function testItReturnsPaymentOptionsAndSelectedModule(): void
+    {
+        $paymentOption = [
+            'module_name' => 'ps_wirepayment',
+            'call_to_action_text' => 'Wire payment',
+            'action' => '/module/ps_wirepayment/validation',
+        ];
+        $selectionKey = (new PaymentSelectionKeyBuilder())->buildSelectionKey($paymentOption);
+
+        $context = CheckoutTestFixtures::context([
+            'cart' => CheckoutTestFixtures::pricedCart(42.0, ['id' => 1]),
+            'country' => CheckoutTestFixtures::country(),
+            'shop' => CheckoutTestFixtures::shop(1),
+        ]);
+        $context->cookie = new class($selectionKey) {
+            /** @var array<string,string> */
+            private array $values;
+
+            public function __construct(string $selectionKey)
+            {
+                $this->values = [
+                    'opc_selected_payment_module' => 'ps_wirepayment',
+                    'opc_selected_payment_selection_key' => $selectionKey,
+                ];
+            }
+
+            public function __get(string $name)
+            {
+                return $this->values[$name] ?? null;
+            }
+
+            public function __unset(string $name): void
+            {
+                unset($this->values[$name]);
+            }
+
+            public function write(): void
+            {
+            }
+        };
+
+        $finder = $this->getMockBuilder(\PaymentOptionsFinder::class)
+            ->disableOriginalConstructor()
+            ->onlyMethods(['present'])
+            ->getMock();
+        $finder->expects($this->once())->method('present')->with(false)->willReturn([
+            'ps_wirepayment' => [
+                0 => $paymentOption,
+            ],
+        ]);
+
+        $handler = new OnePageCheckoutPaymentMethodsHandler($context, $finder);
+        $response = $handler->handle();
+
+        self::assertTrue($response['success']);
+        self::assertSame('ps_wirepayment', $response['selected_payment_module']);
+        self::assertSame($selectionKey, $response['selected_payment_selection_key']);
+        self::assertSame('ps_wirepayment', $response['payment_options']['ps_wirepayment'][0]['module_name']);
+        self::assertNotSame('', $response['payment_options']['ps_wirepayment'][0]['selection_key']);
+        self::assertFalse($response['is_free']);
+    }
+
+    public function testItReturnsStructuredErrorWhenCartIsMissing(): void
+    {
+        $context = CheckoutTestFixtures::context([
+            'cart' => null,
+            'country' => CheckoutTestFixtures::country(),
+        ]);
+
+        $handler = new OnePageCheckoutPaymentMethodsHandler($context);
+        $response = $handler->handle();
+
+        self::assertFalse($response['success']);
+        self::assertArrayHasKey('errors', $response);
+    }
+}
diff --git a/tests/php/Unit/Checkout/Ajax/OpcSaveAddressHandlerTest.php b/tests/php/Unit/Checkout/Ajax/OpcSaveAddressHandlerTest.php
new file mode 100644
index 0000000..e0d5958
--- /dev/null
+++ b/tests/php/Unit/Checkout/Ajax/OpcSaveAddressHandlerTest.php
@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutCustomerContextResolver;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutSaveAddressHandler;
+use Symfony\Contracts\Translation\TranslatorInterface;
+use Tests\Fixtures\CheckoutTestFixtures;
+
+class OpcSaveAddressHandlerTest extends TestCase
+{
+    public function testItReturnsTechnicalErrorsUnderTheErrorsKeyWhenCustomerCannotBeResolved(): void
+    {
+        $translator = $this->createMock(TranslatorInterface::class);
+        $resolver = $this->createMock(CheckoutCustomerContextResolver::class);
+        $resolver->method('resolveId')->willReturn(0);
+
+        $handler = $this->createHandler(CheckoutTestFixtures::context(), $translator, $resolver);
+        $response = $handler->handle([]);
+
+        self::assertSame(
+            [
+                'success' => false,
+                'errors' => [
+                    '' => ['Unable to resolve checkout customer.'],
+                ],
+            ],
+            $response
+        );
+    }
+
+    private function createHandler(
+        \Context $context,
+        TranslatorInterface $translator,
+        CheckoutCustomerContextResolver $resolver,
+    ): OnePageCheckoutSaveAddressHandler {
+        return new OnePageCheckoutSaveAddressHandler($context, $translator, $resolver);
+    }
+}
diff --git a/tests/php/Unit/Checkout/Ajax/OpcSelectPaymentHandlerTest.php b/tests/php/Unit/Checkout/Ajax/OpcSelectPaymentHandlerTest.php
new file mode 100644
index 0000000..e684878
--- /dev/null
+++ b/tests/php/Unit/Checkout/Ajax/OpcSelectPaymentHandlerTest.php
@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutSelectPaymentHandler;
+
+class OpcSelectPaymentHandlerTest extends TestCase
+{
+    public function testItPersistsSelectedPaymentOnCookie(): void
+    {
+        $cookie = new class {
+            /** @var array<string,mixed> */
+            public array $values = [];
+
+            public function __set(string $name, $value): void
+            {
+                $this->values[$name] = $value;
+            }
+
+            public function __get(string $name)
+            {
+                return $this->values[$name] ?? null;
+            }
+
+            public function write(): void
+            {
+            }
+        };
+        $context = new class extends \Context {
+            public function __construct()
+            {
+            }
+        };
+        $context->cookie = $cookie;
+
+        $handler = new OnePageCheckoutSelectPaymentHandler($context);
+        $response = $handler->handle([
+            'payment_option' => 'payment-option-1',
+            'payment_module' => 'ps_wirepayment',
+            'payment_selection_key' => 'ps_wirepayment::selection',
+        ]);
+
+        self::assertTrue($response['success']);
+        self::assertSame('payment-option-1', $cookie->values['opc_selected_payment_option']);
+        self::assertSame('ps_wirepayment', $cookie->values['opc_selected_payment_module']);
+        self::assertSame('ps_wirepayment::selection', $cookie->values['opc_selected_payment_selection_key']);
+    }
+}
diff --git a/tests/php/Unit/Checkout/Ajax/OpcStatesHandlerTest.php b/tests/php/Unit/Checkout/Ajax/OpcStatesHandlerTest.php
new file mode 100644
index 0000000..7d6f6e5
--- /dev/null
+++ b/tests/php/Unit/Checkout/Ajax/OpcStatesHandlerTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutStatesHandler;
+
+class OpcStatesHandlerTest extends TestCase
+{
+    public function testItReturnsEmptyStatesWithoutCountry(): void
+    {
+        $handler = new OnePageCheckoutStatesHandler();
+        $response = $handler->handle([]);
+
+        self::assertTrue($response['success']);
+        self::assertSame([], $response['states']);
+        self::assertFalse($response['contains_states']);
+    }
+}
diff --git a/tests/php/Unit/Checkout/Ajax/OpcSubmitHandlerTest.php b/tests/php/Unit/Checkout/Ajax/OpcSubmitHandlerTest.php
new file mode 100644
index 0000000..ee7725f
--- /dev/null
+++ b/tests/php/Unit/Checkout/Ajax/OpcSubmitHandlerTest.php
@@ -0,0 +1,127 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout\Ajax;
+
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\CheckoutSessionFactory;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\Submit\OnePageCheckoutSubmitHandler;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\Submit\OnePageCheckoutSubmitProcessor;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\Submit\OnePageCheckoutSubmitValidationStateStorage;
+
+class OpcSubmitHandlerTest extends TestCase
+{
+    private \Context $context;
+    private CheckoutSessionFactory|MockObject $checkoutSessionFactory;
+    private OnePageCheckoutSubmitProcessor|MockObject $submitProcessor;
+    private OnePageCheckoutSubmitValidationStateStorage|MockObject $submitValidationStateStorage;
+    private \CheckoutSession|MockObject $checkoutSession;
+    private OnePageCheckoutSubmitHandler $handler;
+
+    protected function setUp(): void
+    {
+        $this->context = $this->createMock(\Context::class);
+        $this->context->cookie = new class {
+            public array $values = [];
+            public bool $written = false;
+
+            public function __set(string $key, string $value): void
+            {
+                $this->values[$key] = $value;
+            }
+
+            public function __get(string $key): string
+            {
+                return $this->values[$key] ?? '';
+            }
+
+            public function write(): void
+            {
+                $this->written = true;
+            }
+        };
+        $this->checkoutSessionFactory = $this->createMock(CheckoutSessionFactory::class);
+        $this->submitProcessor = $this->createMock(OnePageCheckoutSubmitProcessor::class);
+        $this->submitValidationStateStorage = $this->createMock(OnePageCheckoutSubmitValidationStateStorage::class);
+        $this->checkoutSession = $this->createMock(\CheckoutSession::class);
+        $this->checkoutSession->method('getCheckoutURL')->willReturn('/commande');
+
+        $this->checkoutSessionFactory->method('create')->willReturn($this->checkoutSession);
+
+        $this->handler = new OnePageCheckoutSubmitHandler(
+            $this->context,
+            $this->checkoutSessionFactory,
+            $this->submitProcessor,
+            $this->submitValidationStateStorage
+        );
+    }
+
+    public function testHandlePassesRequestParametersAsIs(): void
+    {
+        $this->submitProcessor
+            ->expects($this->once())
+            ->method('process')
+            ->with($this->checkoutSession, $this->callback(static function (array $requestParameters): bool {
+                return !isset($requestParameters['submitOnePageCheckout'])
+                    && $requestParameters['email'] === 'customer@example.com';
+            }))
+            ->willReturn([
+                'success' => true,
+                'validation_errors' => [],
+                'form_errors' => [],
+                'submitted_values' => [],
+            ]);
+        $this->submitValidationStateStorage->expects($this->once())->method('clear');
+
+        $response = $this->handler->handle([
+            'email' => 'customer@example.com',
+            'paymentMethod' => 'ps_checkpayment',
+        ]);
+
+        self::assertTrue($response['success']);
+        self::assertFalse($response['reload']);
+        self::assertSame('/commande', $response['checkout_url']);
+        self::assertSame('ps_checkpayment', $this->context->cookie->__get('opc_selected_payment_module'));
+        self::assertTrue($this->context->cookie->written);
+    }
+
+    public function testHandlePersistsFailedSubmitStateAndReturnsReload(): void
+    {
+        $this->submitProcessor->expects($this->once())
+            ->method('process')
+            ->willReturn([
+                'success' => false,
+                'validation_errors' => [
+                    'payment' => ['paymentMethod' => 'Please select a payment method.'],
+                ],
+                'form_errors' => [
+                    'firstname' => ['Required'],
+                ],
+                'submitted_values' => [
+                    'firstname' => 'Ada',
+                ],
+            ]);
+        $this->submitValidationStateStorage->expects($this->once())
+            ->method('save')
+            ->with([
+                'validation_errors' => [
+                    'payment' => ['paymentMethod' => 'Please select a payment method.'],
+                ],
+                'form_errors' => [
+                    'firstname' => ['Required'],
+                ],
+                'submitted_values' => [
+                    'firstname' => 'Ada',
+                ],
+            ]);
+
+        $response = $this->handler->handle([
+        ]);
+
+        self::assertFalse($response['success']);
+        self::assertTrue($response['reload']);
+        self::assertSame('/commande', $response['checkout_url']);
+    }
+}
diff --git a/tests/php/Unit/Checkout/Ajax/OpcSubmitProcessorTest.php b/tests/php/Unit/Checkout/Ajax/OpcSubmitProcessorTest.php
new file mode 100644
index 0000000..b4b65b2
--- /dev/null
+++ b/tests/php/Unit/Checkout/Ajax/OpcSubmitProcessorTest.php
@@ -0,0 +1,268 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout\Ajax;
+
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\Submit\OnePageCheckoutSubmitProcessor;
+use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutForm;
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class OpcSubmitProcessorTest extends TestCase
+{
+    private \Cart|MockObject $cart;
+    private \Context|MockObject $context;
+    private \CheckoutSession|MockObject $checkoutSession;
+    private OnePageCheckoutForm|MockObject $opcForm;
+    private \PaymentOptionsFinder|MockObject $paymentOptionsFinder;
+    private \ConditionsToApproveFinder|MockObject $conditionsToApproveFinder;
+    private OnePageCheckoutSubmitProcessor $processor;
+
+    protected function setUp(): void
+    {
+        $this->cart = $this->createMock(\Cart::class);
+        $this->cart->method('isVirtualCart')->willReturn(false);
+        $this->cart->method('getOrderTotal')->willReturn(10.0);
+
+        $customer = $this->createMock(\Customer::class);
+        $customer->method('isLogged')->willReturn(true);
+        $customer->method('isGuest')->willReturn(false);
+        $customer->id = 42;
+        $customer->email = 'existing@example.com';
+
+        $language = $this->createMock(\Language::class);
+        $language->id = 1;
+
+        $this->context = $this->createMock(\Context::class);
+        $this->context->cart = $this->cart;
+        $this->context->customer = $customer;
+        $this->context->language = $language;
+        $this->context->cookie = new class {
+            public array $values = [];
+
+            public function __set(string $key, string $value): void
+            {
+                $this->values[$key] = $value;
+            }
+
+            public function __get(string $key): string
+            {
+                return $this->values[$key] ?? '';
+            }
+        };
+
+        $translator = $this->createMock(TranslatorInterface::class);
+        $translator->method('trans')->willReturnArgument(0);
+
+        $this->checkoutSession = $this->createMock(\CheckoutSession::class);
+        $this->checkoutSession->method('getCart')->willReturn($this->cart);
+        $this->checkoutSession->method('getCustomer')->willReturn($customer);
+        $this->checkoutSession->method('getSelectedDeliveryOption')->willReturn('');
+
+        $this->opcForm = $this->createMock(OnePageCheckoutForm::class);
+        $this->opcForm->method('fillWith')->willReturnSelf();
+        $this->paymentOptionsFinder = $this->createMock(\PaymentOptionsFinder::class);
+        $this->conditionsToApproveFinder = $this->createMock(\ConditionsToApproveFinder::class);
+
+        $this->processor = new OnePageCheckoutSubmitProcessor(
+            $this->context,
+            $translator,
+            $this->opcForm,
+            $this->paymentOptionsFinder,
+            $this->conditionsToApproveFinder
+        );
+    }
+
+    public function testProcessNormalizesMissingUseSameAddressFlag(): void
+    {
+        $this->checkoutSession->method('getDeliveryOptions')->willReturn([]);
+        $this->paymentOptionsFinder->method('present')->willReturn([]);
+        $this->conditionsToApproveFinder->method('getConditionsToApproveForTemplate')->willReturn([]);
+        $this->opcForm->expects($this->once())
+            ->method('fillWith')
+            ->with($this->callback(static function (array $parameters): bool {
+                return isset($parameters['use_same_address']) && $parameters['use_same_address'] === '0';
+            }))
+            ->willReturnSelf();
+        $this->opcForm->method('validate')->willReturn(false);
+        $this->opcForm->method('getErrors')->willReturn(['firstname' => ['required']]);
+
+        $response = $this->processor->process($this->checkoutSession, [
+            'email' => 'connected@example.com',
+        ]);
+
+        self::assertFalse($response['success']);
+        self::assertSame('0', $response['submitted_values']['use_same_address']);
+    }
+
+    public function testProcessNormalizesMissingUseSameAddressFlagForVirtualCart(): void
+    {
+        $virtualCart = $this->createMock(\Cart::class);
+        $virtualCart->method('isVirtualCart')->willReturn(true);
+        $virtualCart->method('getOrderTotal')->willReturn(10.0);
+
+        $virtualContext = clone $this->context;
+        $virtualContext->cart = $virtualCart;
+
+        $virtualCheckoutSession = $this->createMock(\CheckoutSession::class);
+        $virtualCheckoutSession->method('getCart')->willReturn($virtualCart);
+        $virtualCheckoutSession->method('getCustomer')->willReturn($this->context->customer);
+        $virtualCheckoutSession->method('getSelectedDeliveryOption')->willReturn('');
+        $virtualCheckoutSession->method('getDeliveryOptions')->willReturn([]);
+
+        $virtualOpcForm = $this->createMock(OnePageCheckoutForm::class);
+        $virtualOpcForm->expects($this->once())
+            ->method('fillWith')
+            ->with($this->callback(static function (array $parameters): bool {
+                return isset($parameters['use_same_address']) && $parameters['use_same_address'] === '1';
+            }))
+            ->willReturnSelf();
+        $virtualOpcForm->method('validate')->willReturn(false);
+        $virtualOpcForm->method('getErrors')->willReturn(['firstname' => ['required']]);
+
+        $processor = new OnePageCheckoutSubmitProcessor(
+            $virtualContext,
+            $this->createMock(TranslatorInterface::class),
+            $virtualOpcForm,
+            $this->paymentOptionsFinder,
+            $this->conditionsToApproveFinder
+        );
+
+        $response = $processor->process($virtualCheckoutSession, [
+            'email' => 'connected@example.com',
+        ]);
+
+        self::assertFalse($response['success']);
+        self::assertSame('1', $response['submitted_values']['use_same_address']);
+    }
+
+    public function testProcessRequiresDeliveryOptionForPhysicalCart(): void
+    {
+        $this->paymentOptionsFinder->method('present')->willReturn([]);
+        $this->conditionsToApproveFinder->method('getConditionsToApproveForTemplate')->willReturn([]);
+        $this->checkoutSession->method('getDeliveryOptions')->willReturn([]);
+        $this->opcForm->method('validate')->willReturn(true);
+        $this->opcForm->method('getErrors')->willReturn([]);
+
+        $response = $this->processor->process($this->checkoutSession, [
+            'email' => 'connected@example.com',
+        ]);
+
+        self::assertFalse($response['success']);
+        self::assertArrayHasKey('shipping', $response['validation_errors']);
+    }
+
+    public function testProcessRequiresPaymentSelectionWhenPaymentOptionsExist(): void
+    {
+        $this->checkoutSession->method('getDeliveryOptions')->willReturn([
+            '1,' => [
+                'is_module' => false,
+            ],
+        ]);
+        $this->paymentOptionsFinder->method('present')->willReturn([
+            'ps_checkpayment' => [[
+                'module_name' => 'ps_checkpayment',
+                'id' => 'payment-option-1',
+            ]],
+        ]);
+        $this->conditionsToApproveFinder->method('getConditionsToApproveForTemplate')->willReturn([]);
+        $this->opcForm->method('validate')->willReturn(true);
+        $this->opcForm->method('getErrors')->willReturn([]);
+
+        $response = $this->processor->process($this->checkoutSession, [
+            'email' => 'connected@example.com',
+            'delivery_option' => '1,',
+        ]);
+
+        self::assertFalse($response['success']);
+        self::assertArrayHasKey('payment', $response['validation_errors']);
+    }
+
+    public function testProcessRequiresConditionsToApprove(): void
+    {
+        $this->paymentOptionsFinder->method('present')->willReturn([]);
+        $this->checkoutSession->method('getDeliveryOptions')->willReturn([
+            '1,' => [
+                'is_module' => false,
+            ],
+        ]);
+        $this->conditionsToApproveFinder->method('getConditionsToApproveForTemplate')->willReturn([
+            'terms-and-conditions' => '<a>Terms</a>',
+        ]);
+        $this->opcForm->method('validate')->willReturn(true);
+        $this->opcForm->method('getErrors')->willReturn([]);
+
+        $response = $this->processor->process($this->checkoutSession, [
+            'email' => 'connected@example.com',
+            'delivery_option' => '1,',
+            'paymentMethod' => 'ps_checkpayment',
+        ]);
+
+        self::assertFalse($response['success']);
+        self::assertArrayHasKey('conditions', $response['validation_errors']);
+    }
+
+    public function testProcessPersistsResolvedDeliveryOptionAndAddressesOnSuccess(): void
+    {
+        $this->paymentOptionsFinder->method('present')->willReturn([]);
+        $this->conditionsToApproveFinder->method('getConditionsToApproveForTemplate')->willReturn([]);
+        $this->checkoutSession->method('getDeliveryOptions')->willReturn([
+            '1,' => [
+                'is_module' => false,
+            ],
+        ]);
+        $this->opcForm->method('validate')->willReturn(true);
+        $this->opcForm->expects($this->exactly(2))->method('fillWith')->willReturnSelf();
+        $this->opcForm->method('submit')->willReturn([
+            'id_address_delivery' => 10,
+            'id_address_invoice' => 10,
+        ]);
+        $this->checkoutSession->expects($this->once())
+            ->method('setDeliveryOption')
+            ->with([10 => '1,']);
+        $this->checkoutSession->expects($this->once())->method('setIdAddressDelivery')->with(10);
+        $this->checkoutSession->expects($this->once())->method('setIdAddressInvoice')->with(10);
+
+        $response = $this->processor->process($this->checkoutSession, [
+            'email' => 'connected@example.com',
+            'delivery_option' => '1,',
+            'paymentMethod' => 'ps_checkpayment',
+            'conditions_to_approve' => [],
+        ]);
+
+        self::assertTrue($response['success']);
+    }
+
+    public function testProcessReturnsAddressErrorsWhenFormSubmitFails(): void
+    {
+        $this->paymentOptionsFinder->method('present')->willReturn([]);
+        $this->conditionsToApproveFinder->method('getConditionsToApproveForTemplate')->willReturn([]);
+        $this->checkoutSession->method('getDeliveryOptions')->willReturn([
+            '1,' => [
+                'is_module' => false,
+            ],
+        ]);
+        $this->opcForm->method('validate')->willReturn(true);
+        $this->opcForm->expects($this->exactly(2))->method('fillWith')->willReturnSelf();
+        $this->opcForm->method('submit')->willReturn(false);
+        $this->opcForm->method('getErrors')->willReturn([
+            'address1' => ['Address is invalid.'],
+        ]);
+
+        $response = $this->processor->process($this->checkoutSession, [
+            'email' => 'connected@example.com',
+            'delivery_option' => '1,',
+            'paymentMethod' => 'ps_checkpayment',
+            'conditions_to_approve' => [],
+        ]);
+
+        self::assertFalse($response['success']);
+        self::assertSame([
+            'address' => [
+                'address1' => ['Address is invalid.'],
+            ],
+        ], $response['validation_errors']);
+    }
+}
diff --git a/tests/php/Unit/Checkout/Ajax/TempAddressCarrierSelectionStorageTest.php b/tests/php/Unit/Checkout/Ajax/TempAddressCarrierSelectionStorageTest.php
new file mode 100644
index 0000000..8ab0f64
--- /dev/null
+++ b/tests/php/Unit/Checkout/Ajax/TempAddressCarrierSelectionStorageTest.php
@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout\Ajax;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\TempAddressCarrierSelectionStorage;
+
+class TempAddressCarrierSelectionStorageTest extends TestCase
+{
+    public function testItSavesAndClearsTheTemporaryCarrierSelection(): void
+    {
+        $cookie = new class {
+            /** @var array<string,string> */
+            public array $values = [];
+            public int $writes = 0;
+
+            public function __get(string $name)
+            {
+                return $this->values[$name] ?? null;
+            }
+
+            public function __set(string $name, string $value): void
+            {
+                $this->values[$name] = $value;
+            }
+
+            public function __unset(string $name): void
+            {
+                unset($this->values[$name]);
+            }
+
+            public function write(): void
+            {
+                ++$this->writes;
+            }
+        };
+
+        $context = new \Context();
+        $context->cookie = $cookie;
+
+        $storage = new TempAddressCarrierSelectionStorage($context);
+
+        self::assertSame('', $storage->get());
+
+        $storage->save('2,');
+        self::assertSame('2,', $storage->get());
+
+        $storage->clear();
+        self::assertSame('', $storage->get());
+        self::assertSame(2, $cookie->writes);
+    }
+}
diff --git a/tests/php/Unit/Checkout/CheckoutOnePageStepRenderTest.php b/tests/php/Unit/Checkout/CheckoutOnePageStepRenderTest.php
new file mode 100644
index 0000000..e0c181b
--- /dev/null
+++ b/tests/php/Unit/Checkout/CheckoutOnePageStepRenderTest.php
@@ -0,0 +1,194 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\CheckoutOnePageStep;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\PaymentSelectionKeyBuilder;
+use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutForm;
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class CheckoutOnePageStepRenderTest extends TestCase
+{
+    public function testRenderInjectsOpcFormTemplateVariablesIntoStepTemplate(): void
+    {
+        $smarty = $this->getMockBuilder(\Smarty::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $context = new class extends \Context {
+            public function __construct()
+            {
+            }
+        };
+        $context->smarty = $smarty;
+        $context->cart = new class extends \Cart {
+            public function __construct()
+            {
+            }
+
+            public function isVirtualCart()
+            {
+                return false;
+            }
+
+            public function getOrderTotal(
+                $withTaxes = true,
+                $type = \Cart::BOTH,
+                $products = null,
+                $id_carrier = null,
+                $use_cache = false,
+                bool $keepOrderPrices = false,
+            ) {
+                return 10.0;
+            }
+        };
+        $context->cookie = new class {
+            public function __get(string $name)
+            {
+                return '';
+            }
+        };
+        $context->controller = new class {
+            public function getTemplateVarConfiguration(): array
+            {
+                return [
+                    'display_taxes_label' => true,
+                ];
+            }
+        };
+
+        $translator = $this->createMock(TranslatorInterface::class);
+        $translator->method('trans')->willReturn('');
+
+        $opcForm = $this->getMockBuilder(OnePageCheckoutForm::class)
+            ->disableOriginalConstructor()
+            ->onlyMethods(['getTemplateVariables'])
+            ->getMock();
+        $opcForm->expects($this->once())
+            ->method('getTemplateVariables')
+            ->willReturn([
+                'contactFields' => ['email' => ['value' => 'john@example.com']],
+                'additionalCustomerFields' => [],
+                'useSameAddressField' => ['value' => true],
+                'deliveryFields' => ['firstname' => ['name' => 'firstname']],
+                'invoiceFields' => ['invoice_firstname' => ['name' => 'invoice_firstname']],
+                'invoiceMetaFields' => [],
+                'errors' => ['' => []],
+                'token' => 'token',
+            ]);
+
+        $paymentOptionsFinder = $this->getMockBuilder(\PaymentOptionsFinder::class)
+            ->disableOriginalConstructor()
+            ->onlyMethods(['present'])
+            ->getMock();
+        $paymentOptionsFinder->method('present')->willReturn([]);
+
+        $conditionsToApproveFinder = $this->getMockBuilder(\ConditionsToApproveFinder::class)
+            ->disableOriginalConstructor()
+            ->onlyMethods(['getConditionsToApproveForTemplate'])
+            ->getMock();
+        $conditionsToApproveFinder->method('getConditionsToApproveForTemplate')->willReturn([]);
+
+        $checkoutSession = new class($context->cart) {
+            private \Cart $cart;
+
+            public function __construct(\Cart $cart)
+            {
+                $this->cart = $cart;
+            }
+
+            public function getCart()
+            {
+                return $this->cart;
+            }
+
+            public function getIdAddressDelivery()
+            {
+                return 0;
+            }
+
+            public function getIdAddressInvoice()
+            {
+                return 0;
+            }
+
+            public function getDeliveryOptions()
+            {
+                return [];
+            }
+
+            public function getSelectedDeliveryOption()
+            {
+                return '';
+            }
+
+            public function isRecyclable()
+            {
+                return false;
+            }
+
+            public function getMessage()
+            {
+                return '';
+            }
+
+            public function getGift()
+            {
+                return [
+                    'isGift' => false,
+                    'message' => '',
+                ];
+            }
+        };
+
+        $step = new class($context, $translator, $opcForm, $paymentOptionsFinder, $conditionsToApproveFinder, new PaymentSelectionKeyBuilder(), $checkoutSession) extends CheckoutOnePageStep {
+            public array $capturedParams = [];
+            private object $checkoutSessionStub;
+
+            public function __construct(
+                \Context $context,
+                TranslatorInterface $translator,
+                OnePageCheckoutForm $opcForm,
+                \PaymentOptionsFinder $paymentOptionsFinder,
+                \ConditionsToApproveFinder $conditionsToApproveFinder,
+                PaymentSelectionKeyBuilder $paymentSelectionKeyBuilder,
+                object $checkoutSessionStub,
+            ) {
+                parent::__construct(
+                    $context,
+                    $translator,
+                    $opcForm,
+                    $paymentOptionsFinder,
+                    $conditionsToApproveFinder,
+                    $paymentSelectionKeyBuilder
+                );
+                $this->checkoutSessionStub = $checkoutSessionStub;
+            }
+
+            public function getCheckoutSession()
+            {
+                return $this->checkoutSessionStub;
+            }
+
+            protected function renderTemplate($template, array $extraParams = [], array $params = [])
+            {
+                $this->capturedParams = $params;
+
+                return 'rendered';
+            }
+        };
+
+        self::assertSame('rendered', $step->render());
+        self::assertArrayHasKey('contactFields', $step->capturedParams);
+        self::assertArrayHasKey('deliveryFields', $step->capturedParams);
+        self::assertArrayHasKey('invoiceFields', $step->capturedParams);
+        self::assertArrayHasKey('errors', $step->capturedParams);
+        self::assertArrayHasKey('configuration', $step->capturedParams);
+        self::assertArrayHasKey('is_guest_checkout_enabled', $step->capturedParams['configuration']);
+        self::assertIsBool($step->capturedParams['configuration']['is_guest_checkout_enabled']);
+        self::assertArrayNotHasKey('opc_form', $step->capturedParams);
+    }
+}
diff --git a/tests/php/Unit/Checkout/CheckoutOnePageStepRequestPersistenceTest.php b/tests/php/Unit/Checkout/CheckoutOnePageStepRequestPersistenceTest.php
new file mode 100644
index 0000000..70a0d07
--- /dev/null
+++ b/tests/php/Unit/Checkout/CheckoutOnePageStepRequestPersistenceTest.php
@@ -0,0 +1,229 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout;
+
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\CheckoutOnePageStep;
+use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutForm;
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class TestableCheckoutOnePageStep extends CheckoutOnePageStep
+{
+    private \CheckoutProcess $mockProcess;
+
+    public function setMockProcess(\CheckoutProcess $process): void
+    {
+        $this->mockProcess = $process;
+    }
+
+    public function getCheckoutProcess(): \CheckoutProcess
+    {
+        return $this->mockProcess;
+    }
+}
+
+class CheckoutOnePageStepRequestPersistenceTest extends TestCase
+{
+    private \Cart|MockObject $cart;
+    private \Context|MockObject $context;
+    private \CheckoutSession|MockObject $session;
+    private \CheckoutProcess|MockObject $checkoutProcess;
+    private OnePageCheckoutForm|MockObject $opcForm;
+    private \PaymentOptionsFinder|MockObject $paymentOptionsFinder;
+    private \ConditionsToApproveFinder|MockObject $conditionsToApproveFinder;
+    private TestableCheckoutOnePageStep $step;
+
+    protected function setUp(): void
+    {
+        $this->cart = $this->createMock(\Cart::class);
+        $this->cart->method('isVirtualCart')->willReturn(false);
+        $this->cart->method('getOrderTotal')->willReturn(10.0);
+
+        $customer = $this->createMock(\Customer::class);
+        $customer->method('isLogged')->willReturn(true);
+        $customer->method('isGuest')->willReturn(false);
+        $customer->id = 42;
+        $customer->email = 'existing@example.com';
+
+        $language = $this->createMock(\Language::class);
+        $language->id = 1;
+
+        $this->context = $this->createMock(\Context::class);
+        $this->context->cart = $this->cart;
+        $this->context->customer = $customer;
+        $this->context->language = $language;
+        $this->context->smarty = $this->createMock(\Smarty::class);
+        $this->context->cookie = new class {
+            public array $values = [];
+
+            public function __set(string $key, string $value): void
+            {
+                $this->values[$key] = $value;
+            }
+
+            public function __get(string $key): string
+            {
+                return $this->values[$key] ?? '';
+            }
+
+            public function __unset(string $key): void
+            {
+                unset($this->values[$key]);
+            }
+
+            public function write(): void
+            {
+            }
+        };
+
+        $this->session = $this->createMock(\CheckoutSession::class);
+        $this->session->method('getCart')->willReturn($this->cart);
+        $this->session->method('getCustomer')->willReturn($customer);
+        $this->session->method('getIdAddressDelivery')->willReturn(0);
+        $this->session->method('getIdAddressInvoice')->willReturn(0);
+
+        $this->checkoutProcess = $this->createMock(\CheckoutProcess::class);
+        $this->checkoutProcess->method('getCheckoutSession')->willReturn($this->session);
+
+        $translator = $this->createMock(TranslatorInterface::class);
+        $translator->method('trans')->willReturnArgument(0);
+
+        $this->opcForm = $this->createMock(OnePageCheckoutForm::class);
+        $this->paymentOptionsFinder = $this->createMock(\PaymentOptionsFinder::class);
+        $this->conditionsToApproveFinder = $this->createMock(\ConditionsToApproveFinder::class);
+
+        $this->step = new TestableCheckoutOnePageStep(
+            $this->context,
+            $translator,
+            $this->opcForm,
+            $this->paymentOptionsFinder,
+            $this->conditionsToApproveFinder
+        );
+        $this->step->setMockProcess($this->checkoutProcess);
+    }
+
+    public function testDeliveryOptionArrayIsPersisted(): void
+    {
+        $this->session->expects($this->once())
+            ->method('setDeliveryOption')
+            ->with([5 => '1,']);
+
+        $this->step->handleRequest(['delivery_option' => [5 => '1,']]);
+    }
+
+    public function testDeliveryOptionStringIsNotPersisted(): void
+    {
+        $this->session->expects($this->never())
+            ->method('setDeliveryOption');
+
+        $this->step->handleRequest(['delivery_option' => '1,']);
+    }
+
+    public function testDeliveryOptionArrayIsPersistedWithoutSubmitSpecificBranch(): void
+    {
+        $this->session->expects($this->once())
+            ->method('setDeliveryOption')
+            ->with([5 => '1,']);
+
+        $this->step->handleRequest([
+            'delivery_option' => [5 => '1,'],
+        ]);
+    }
+
+    public function testPersistedValidationErrorsAreFlushedAfterFirstRestore(): void
+    {
+        $this->step->restorePersistedData([
+            'validation_errors' => [
+                'payment' => [
+                    'paymentMethod' => 'Please select a payment method.',
+                ],
+            ],
+        ]);
+
+        self::assertSame([
+            'payment' => [
+                'paymentMethod' => 'Please select a payment method.',
+            ],
+        ], $this->step->getValidationErrors());
+        self::assertSame([
+            'validation_errors' => [],
+        ], $this->step->getDataToPersist());
+    }
+
+    public function testStepRestoresLastFailedSubmitStateFromModuleStorage(): void
+    {
+        $this->context->cookie->__set('opc_submit_validation_state', json_encode([
+            'validation_errors' => [
+                'payment' => [
+                    'paymentMethod' => 'Please select a payment method.',
+                ],
+            ],
+            'form_errors' => [
+                'firstname' => ['The firstname field is required.'],
+            ],
+            'submitted_values' => [
+                'firstname' => 'Ada',
+                'use_same_address' => '0',
+            ],
+        ]));
+
+        $this->opcForm->expects($this->once())
+            ->method('restoreSubmissionState')
+            ->with(
+                [
+                    'firstname' => 'Ada',
+                    'use_same_address' => '0',
+                ],
+                [
+                    'firstname' => ['The firstname field is required.'],
+                ]
+            )
+            ->willReturnSelf();
+
+        $this->step->handleRequest([]);
+
+        self::assertSame([
+            'payment' => [
+                'paymentMethod' => 'Please select a payment method.',
+            ],
+        ], $this->step->getValidationErrors());
+        self::assertSame([
+            'validation_errors' => [],
+        ], $this->step->getDataToPersist());
+        self::assertSame('', $this->context->cookie->__get('opc_submit_validation_state'));
+    }
+
+    public function testDeliveryOptionNotPersistedOnVirtualCart(): void
+    {
+        $cart = $this->createMock(\Cart::class);
+        $cart->method('isVirtualCart')->willReturn(true);
+
+        $session = $this->createMock(\CheckoutSession::class);
+        $session->method('getCart')->willReturn($cart);
+        $session->expects($this->never())->method('setDeliveryOption');
+        $session->method('getCustomer')->willReturn($this->context->customer);
+        $session->method('getIdAddressDelivery')->willReturn(0);
+        $session->method('getIdAddressInvoice')->willReturn(0);
+
+        $checkoutProcess = $this->createMock(\CheckoutProcess::class);
+        $checkoutProcess->method('getCheckoutSession')->willReturn($session);
+
+        $context = clone $this->context;
+        $context->cart = $cart;
+
+        $step = new TestableCheckoutOnePageStep(
+            $context,
+            $this->createMock(TranslatorInterface::class),
+            $this->opcForm,
+            $this->createMock(\PaymentOptionsFinder::class),
+            $this->createMock(\ConditionsToApproveFinder::class)
+        );
+        $step->setMockProcess($checkoutProcess);
+        $step->handleRequest(['delivery_option' => [5 => '1,']]);
+
+        self::assertTrue(true);
+    }
+}
diff --git a/tests/php/Unit/Checkout/CheckoutOnePageStepSpe7Test.php b/tests/php/Unit/Checkout/CheckoutOnePageStepSpe7Test.php
new file mode 100644
index 0000000..848b5be
--- /dev/null
+++ b/tests/php/Unit/Checkout/CheckoutOnePageStepSpe7Test.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\CheckoutOnePageStep;
+
+class CheckoutOnePageStepSpe7Test extends TestCase
+{
+    public function testItReadsSelectedPaymentModuleFromCookie(): void
+    {
+        $reflection = new \ReflectionClass(CheckoutOnePageStep::class);
+        /** @var CheckoutOnePageStep $step */
+        $step = $reflection->newInstanceWithoutConstructor();
+
+        $context = new class extends \Context {
+            public function __construct()
+            {
+            }
+        };
+        $context->cookie = new class {
+            public function __get(string $name)
+            {
+                return $name === 'opc_selected_payment_module' ? 'ps_wirepayment' : null;
+            }
+        };
+
+        $contextProperty = new \ReflectionProperty(\AbstractCheckoutStep::class, 'context');
+        $contextProperty->setAccessible(true);
+        $contextProperty->setValue($step, $context);
+
+        $method = $reflection->getMethod('getSelectedPaymentModule');
+        $method->setAccessible(true);
+
+        self::assertSame('ps_wirepayment', $method->invoke($step));
+    }
+}
diff --git a/tests/php/Unit/Checkout/CheckoutOnePageStepTest.php b/tests/php/Unit/Checkout/CheckoutOnePageStepTest.php
deleted file mode 100644
index 88c5940..0000000
--- a/tests/php/Unit/Checkout/CheckoutOnePageStepTest.php
+++ /dev/null
@@ -1,25 +0,0 @@
-<?php
-
-/**
- * For the full copyright and license information, please view the
- * docs/licenses/LICENSE.txt file that was distributed with this source code.
- */
-
-declare(strict_types=1);
-
-namespace Tests\Unit\Checkout;
-
-use PHPUnit\Framework\TestCase;
-use PrestaShop\Module\PsOnePageCheckout\Checkout\CheckoutOnePageStep;
-
-class CheckoutOnePageStepTest extends TestCase
-{
-    public function testItKeepsStableIdentifierForPersistedCheckoutData(): void
-    {
-        $reflection = new \ReflectionClass(CheckoutOnePageStep::class);
-        /** @var CheckoutOnePageStep $step */
-        $step = $reflection->newInstanceWithoutConstructor();
-
-        self::assertSame('checkout-one-page-step', $step->getIdentifier());
-    }
-}
diff --git a/tests/php/Unit/Checkout/ExistingCustomerStateTest.php b/tests/php/Unit/Checkout/ExistingCustomerStateTest.php
index 2c367f9..8faf330 100644
--- a/tests/php/Unit/Checkout/ExistingCustomerStateTest.php
+++ b/tests/php/Unit/Checkout/ExistingCustomerStateTest.php
@@ -34,6 +34,11 @@ public function testItBuildsAGuestStateFromCustomer(): void
             public function __construct()
             {
             }
+
+            public function isGuest(): bool
+            {
+                return (bool) $this->is_guest;
+            }
         };
         $customer->id = 42;
         $customer->is_guest = 1;
@@ -52,6 +57,11 @@ public function testItBuildsARegisteredStateFromCustomer(): void
             public function __construct()
             {
             }
+
+            public function isGuest(): bool
+            {
+                return (bool) $this->is_guest;
+            }
         };
         $customer->id = 99;
         $customer->is_guest = 0;
diff --git a/tests/php/Unit/Checkout/OpcCheckoutProcessBuilderTest.php b/tests/php/Unit/Checkout/OpcCheckoutProcessBuilderTest.php
index 5c3ebe2..a0b559c 100644
--- a/tests/php/Unit/Checkout/OpcCheckoutProcessBuilderTest.php
+++ b/tests/php/Unit/Checkout/OpcCheckoutProcessBuilderTest.php
@@ -16,6 +16,7 @@
 use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutForm;
 use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutFormFactory;
 use Symfony\Contracts\Translation\TranslatorInterface;
+use Tests\Fixtures\CheckoutTestFixtures;
 
 class OpcCheckoutProcessBuilderTest extends TestCase
 {
@@ -80,26 +81,10 @@ public function testItConfiguresDeliveryOptionsForNonVirtualCart(): void
 
     private function createContextWithCart(bool $isVirtual): \Context
     {
-        $context = new class extends \Context {
-            public function __construct()
-            {
-            }
-        };
-        $context->cart = new class($isVirtual) extends \Cart {
-            private bool $isVirtual;
-
-            public function __construct(bool $isVirtual)
-            {
-                $this->isVirtual = $isVirtual;
-            }
-
-            public function isVirtualCart()
-            {
-                return $this->isVirtual;
-            }
-        };
-
-        return $context;
+        return CheckoutTestFixtures::context([
+            'cart' => CheckoutTestFixtures::virtualCart($isVirtual),
+            'smarty' => CheckoutTestFixtures::smarty(),
+        ]);
     }
 }
 
diff --git a/tests/php/Unit/Checkout/PaymentSelectionKeyBuilderTest.php b/tests/php/Unit/Checkout/PaymentSelectionKeyBuilderTest.php
new file mode 100644
index 0000000..f19e5a3
--- /dev/null
+++ b/tests/php/Unit/Checkout/PaymentSelectionKeyBuilderTest.php
@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Checkout;
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\PaymentSelectionKeyBuilder;
+
+class PaymentSelectionKeyBuilderTest extends TestCase
+{
+    public function testItIgnoresRenderOnlyOptionIdWhenBuildingSelectionKey(): void
+    {
+        $builder = new PaymentSelectionKeyBuilder();
+
+        $baseOption = [
+            'id' => 'payment-option-1',
+            'module_name' => 'ps_wirepayment',
+            'action' => '/module/ps_wirepayment/validation',
+            'call_to_action_text' => 'Wire payment',
+            'inputs' => [
+                ['name' => 'token', 'type' => 'hidden'],
+            ],
+        ];
+
+        $firstKey = $builder->buildSelectionKey($baseOption);
+        $secondKey = $builder->buildSelectionKey(array_merge($baseOption, ['id' => 'payment-option-999']));
+
+        self::assertSame($firstKey, $secondKey);
+    }
+
+    public function testItChangesSelectionKeyWhenBusinessSignatureChanges(): void
+    {
+        $builder = new PaymentSelectionKeyBuilder();
+
+        $firstKey = $builder->buildSelectionKey([
+            'module_name' => 'ps_wirepayment',
+            'action' => '/module/ps_wirepayment/validation',
+            'call_to_action_text' => 'Wire payment',
+            'inputs' => [
+                ['name' => 'token', 'type' => 'hidden'],
+            ],
+        ]);
+
+        $secondKey = $builder->buildSelectionKey([
+            'module_name' => 'ps_wirepayment',
+            'action' => '/module/ps_wirepayment/alternate',
+            'call_to_action_text' => 'Wire payment',
+            'inputs' => [
+                ['name' => 'token', 'type' => 'hidden'],
+            ],
+        ]);
+
+        self::assertNotSame($firstKey, $secondKey);
+    }
+}
diff --git a/tests/php/Unit/Controller/AddressFormControllerTest.php b/tests/php/Unit/Controller/AddressFormControllerTest.php
index ae673c6..26199e9 100644
--- a/tests/php/Unit/Controller/AddressFormControllerTest.php
+++ b/tests/php/Unit/Controller/AddressFormControllerTest.php
@@ -16,6 +16,7 @@
 use PHPUnit\Framework\TestCase;
 use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\OnePageCheckoutAddressFormHandler;
 use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutFormFactory;
+use Tests\Fixtures\CheckoutTestFixtures;
 
 class AddressFormControllerTest extends TestCase
 {
@@ -24,7 +25,7 @@ public function testHandleAddressFormRefreshReturnsTechnicalErrorWhenModuleIsDis
         $controller = new TestAddressFormController();
         $controller->module = $this->createDisabledModule();
 
-        $response = $controller->callHandleAddressFormRefresh();
+        $response = $controller->callHandleOpcRequest();
 
         self::assertFalse($response['success']);
         self::assertSame('technical-error', $response['error']);
@@ -34,6 +35,7 @@ public function testHandleAddressFormRefreshReturnsRenderedPartialWhenEnabled():
     {
         $controller = new TestAddressFormController();
         $controller->module = $this->createEnabledModule();
+        $controller->setTestContext($this->createControllerContext());
 
         $handler = $this->getMockBuilder(OnePageCheckoutAddressFormHandler::class)
             ->disableOriginalConstructor()
@@ -52,9 +54,9 @@ public function testHandleAddressFormRefreshReturnsRenderedPartialWhenEnabled():
             ->disableOriginalConstructor()
             ->getMock();
 
-        $response = $controller->callHandleAddressFormRefresh();
+        $response = $controller->callHandleOpcRequest();
 
-        self::assertSame('rendered:checkout/_partials/one-page-checkout-form', $response['address_form']);
+        self::assertSame('rendered:checkout/_partials/one-page-checkout/addresses-section', $response['addresses_section']);
     }
 
     public function testHandleAddressFormRefreshReturnsTechnicalErrorOnRuntimeException(): void
@@ -70,7 +72,7 @@ public function testHandleAddressFormRefreshReturnsTechnicalErrorOnRuntimeExcept
             return true;
         }, E_WARNING);
         try {
-            $response = $controller->callHandleAddressFormRefresh();
+            $response = $controller->callHandleOpcRequest();
         } finally {
             restore_error_handler();
         }
@@ -88,6 +90,33 @@ private function createDisabledModule(): \Ps_Onepagecheckout
     {
         return new DisabledPsOnepagecheckoutModuleForAddressForm();
     }
+
+    private function createControllerContext(): \Context
+    {
+        return CheckoutTestFixtures::context([
+            'smarty' => CheckoutTestFixtures::smarty(),
+            'customer' => CheckoutTestFixtures::customer(
+                [
+                    [
+                        'id' => 0,
+                        'alias' => 'Home',
+                    ],
+                ],
+                false,
+                true,
+                [
+                    'id' => 42,
+                    'firstname' => 'Alice',
+                    'lastname' => 'Doe',
+                    'id_gender' => 0,
+                    'id_risk' => 0,
+                    'is_guest' => true,
+                ]
+            ),
+            'language' => CheckoutTestFixtures::language(1),
+            'cart' => CheckoutTestFixtures::cart(),
+        ]);
+    }
 }
 
 class TestAddressFormController extends \Ps_OnepagecheckoutAddressFormModuleFrontController
@@ -100,9 +129,14 @@ public function __construct()
     {
     }
 
-    public function callHandleAddressFormRefresh(): array
+    public function callHandleOpcRequest(): array
+    {
+        return $this->handleOpcRequest();
+    }
+
+    public function setTestContext(\Context $context): void
     {
-        return $this->handleAddressFormRefresh();
+        $this->context = $context;
     }
 
     protected function createAddressFormHandler(OnePageCheckoutFormFactory $opcFormFactory): OnePageCheckoutAddressFormHandler
diff --git a/tests/php/Unit/Controller/AddressesListControllerTest.php b/tests/php/Unit/Controller/AddressesListControllerTest.php
new file mode 100644
index 0000000..d28fc5f
--- /dev/null
+++ b/tests/php/Unit/Controller/AddressesListControllerTest.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Controller;
+
+if (!defined('_DB_PREFIX_')) {
+    define('_DB_PREFIX_', 'ps_');
+}
+
+use PHPUnit\Framework\TestCase;
+
+class AddressesListControllerTest extends TestCase
+{
+    public function testHandleAddressesListReturnsTechnicalErrorWhenModuleIsDisabled(): void
+    {
+        $controller = new class extends \Ps_OnepagecheckoutAddressesListModuleFrontController {
+            public function __construct()
+            {
+            }
+
+            public function callHandleOpcRequest(): array
+            {
+                return $this->handleOpcRequest();
+            }
+
+            protected function buildTechnicalErrorResponse(): array
+            {
+                return ['success' => false, 'error' => 'technical-error'];
+            }
+        };
+        $controller->module = new class extends \Ps_Onepagecheckout {
+            public function __construct()
+            {
+            }
+
+            public function isOnePageCheckoutEnabled(): bool
+            {
+                return false;
+            }
+        };
+
+        self::assertSame('technical-error', $controller->callHandleOpcRequest()['error']);
+    }
+}
diff --git a/tests/php/Unit/Controller/AdminPsOnePageCheckoutControllerTest.php b/tests/php/Unit/Controller/AdminPsOnePageCheckoutControllerTest.php
index 733f42c..f0d49d1 100644
--- a/tests/php/Unit/Controller/AdminPsOnePageCheckoutControllerTest.php
+++ b/tests/php/Unit/Controller/AdminPsOnePageCheckoutControllerTest.php
@@ -37,10 +37,29 @@ public function testItReturnsEmptyStringWhenModuleIsNotPsOnepagecheckout(): void
 
         self::assertSame('', $controller->callGetBackOfficeConfigurationContent());
     }
+
+    public function testViewAccessRequiresLegacyViewAndModuleConfigurePermission(): void
+    {
+        $controller = new TestAdminPsOnePageCheckoutController();
+        $controller->legacyViewAccess = true;
+        $controller->moduleConfigurePermission = true;
+
+        self::assertTrue($controller->viewAccess());
+
+        $controller->moduleConfigurePermission = false;
+        self::assertFalse($controller->viewAccess());
+
+        $controller->legacyViewAccess = false;
+        $controller->moduleConfigurePermission = true;
+        self::assertFalse($controller->viewAccess());
+    }
 }
 
 class TestAdminPsOnePageCheckoutController extends \AdminPsOnePageCheckoutController
 {
+    public bool $legacyViewAccess = true;
+    public bool $moduleConfigurePermission = true;
+
     public function __construct()
     {
     }
@@ -49,4 +68,14 @@ public function callGetBackOfficeConfigurationContent(): string
     {
         return $this->getBackOfficeConfigurationContent();
     }
+
+    protected function hasLegacyViewAccess(bool $disable = false): bool
+    {
+        return $this->legacyViewAccess;
+    }
+
+    protected function hasModuleConfigurePermission(): bool
+    {
+        return $this->moduleConfigurePermission;
+    }
 }
diff --git a/tests/php/Unit/Controller/CarriersControllerTest.php b/tests/php/Unit/Controller/CarriersControllerTest.php
new file mode 100644
index 0000000..15f1358
--- /dev/null
+++ b/tests/php/Unit/Controller/CarriersControllerTest.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Controller;
+
+if (!defined('_DB_PREFIX_')) {
+    define('_DB_PREFIX_', 'ps_');
+}
+
+use PHPUnit\Framework\TestCase;
+
+class CarriersControllerTest extends TestCase
+{
+    public function testHandleCarriersReturnsTechnicalErrorWhenModuleIsDisabled(): void
+    {
+        $controller = new class extends \Ps_OnepagecheckoutCarriersModuleFrontController {
+            public function __construct()
+            {
+            }
+
+            public function callHandleOpcRequest(): array
+            {
+                return $this->handleOpcRequest();
+            }
+
+            protected function buildTechnicalErrorResponse(): array
+            {
+                return ['success' => false, 'error' => 'technical-error'];
+            }
+        };
+        $controller->module = new class extends \Ps_Onepagecheckout {
+            public function __construct()
+            {
+            }
+
+            public function isOnePageCheckoutEnabled(): bool
+            {
+                return false;
+            }
+        };
+
+        self::assertSame('technical-error', $controller->callHandleOpcRequest()['error']);
+    }
+}
diff --git a/tests/php/Unit/Controller/GuestInitControllerTest.php b/tests/php/Unit/Controller/GuestInitControllerTest.php
index c42cb8c..e43da96 100644
--- a/tests/php/Unit/Controller/GuestInitControllerTest.php
+++ b/tests/php/Unit/Controller/GuestInitControllerTest.php
@@ -24,7 +24,7 @@ public function testHandleGuestInitReturnsTechnicalErrorWhenModuleIsDisabled():
         $controller = new TestGuestInitController();
         $controller->module = $this->createDisabledModule();
 
-        $response = $controller->callHandleGuestInit();
+        $response = $controller->callHandleOpcRequest();
 
         self::assertFalse($response['success']);
         self::assertSame('technical-error', $response['error']);
@@ -53,7 +53,7 @@ public function testHandleGuestInitReturnsHandlerPayloadWhenModuleIsEnabled(): v
             ->disableOriginalConstructor()
             ->getMock();
 
-        $response = $controller->callHandleGuestInit();
+        $response = $controller->callHandleOpcRequest();
 
         self::assertTrue($response['success']);
         self::assertSame(42, $response['id_customer']);
@@ -72,7 +72,7 @@ public function testHandleGuestInitReturnsTechnicalErrorOnRuntimeException(): vo
             return true;
         }, E_WARNING);
         try {
-            $response = $controller->callHandleGuestInit();
+            $response = $controller->callHandleOpcRequest();
         } finally {
             restore_error_handler();
         }
@@ -102,9 +102,9 @@ public function __construct()
     {
     }
 
-    public function callHandleGuestInit(): array
+    public function callHandleOpcRequest(): array
     {
-        return $this->handleGuestInit();
+        return $this->handleOpcRequest();
     }
 
     protected function createGuestInitHandler(OnePageCheckoutFormFactory $opcFormFactory): OnePageCheckoutGuestInitHandler
diff --git a/tests/php/Unit/Controller/OpcSubmitControllerTest.php b/tests/php/Unit/Controller/OpcSubmitControllerTest.php
new file mode 100644
index 0000000..9daa944
--- /dev/null
+++ b/tests/php/Unit/Controller/OpcSubmitControllerTest.php
@@ -0,0 +1,124 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Controller;
+
+if (!defined('_DB_PREFIX_')) {
+    define('_DB_PREFIX_', 'ps_');
+}
+
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Checkout\Ajax\Submit\OnePageCheckoutSubmitHandler;
+
+class OpcSubmitControllerTest extends TestCase
+{
+    public function testHandleOpcSubmitReturnsTechnicalErrorWhenModuleIsDisabled(): void
+    {
+        $controller = new TestOpcSubmitController();
+        $controller->module = new class extends \Ps_Onepagecheckout {
+            public function __construct()
+            {
+            }
+
+            public function isOnePageCheckoutEnabled(): bool
+            {
+                return false;
+            }
+        };
+
+        $response = $controller->callHandleOpcRequest();
+
+        self::assertFalse($response['success']);
+        self::assertSame('technical-error', $response['error']);
+    }
+
+    public function testHandleOpcSubmitReturnsHandlerPayloadWhenModuleIsEnabled(): void
+    {
+        $_SERVER['REQUEST_METHOD'] = 'POST';
+
+        $controller = new TestOpcSubmitController();
+        $controller->module = new class extends \Ps_Onepagecheckout {
+            public function __construct()
+            {
+            }
+
+            public function isOnePageCheckoutEnabled(): bool
+            {
+                return true;
+            }
+        };
+        $controller->submitHandler = $this->getMockBuilder(OnePageCheckoutSubmitHandler::class)
+            ->disableOriginalConstructor()
+            ->onlyMethods(['handle'])
+            ->getMock();
+        $controller->submitHandler
+            ->expects($this->once())
+            ->method('handle')
+            ->willReturn([
+                'success' => true,
+                'reload' => false,
+                'checkout_url' => '/commande',
+            ]);
+
+        $response = $controller->callHandleOpcRequest();
+
+        self::assertTrue($response['success']);
+        self::assertFalse($response['reload']);
+    }
+
+    public function testHandleOpcSubmitRejectsNonPostRequests(): void
+    {
+        $_SERVER['REQUEST_METHOD'] = 'GET';
+
+        $controller = new TestOpcSubmitController();
+        $controller->module = new class extends \Ps_Onepagecheckout {
+            public function __construct()
+            {
+            }
+
+            public function isOnePageCheckoutEnabled(): bool
+            {
+                return true;
+            }
+        };
+
+        $response = $controller->callHandleOpcRequest();
+
+        self::assertFalse($response['success']);
+        self::assertTrue($response['reload']);
+    }
+}
+
+class TestOpcSubmitController extends \Ps_OnepagecheckoutOpcSubmitModuleFrontController
+{
+    public ?OnePageCheckoutSubmitHandler $submitHandler = null;
+
+    public function __construct()
+    {
+    }
+
+    public function callHandleOpcRequest(): array
+    {
+        return $this->handleOpcRequest();
+    }
+
+    protected function createSubmitHandler(): OnePageCheckoutSubmitHandler
+    {
+        if (!$this->submitHandler instanceof OnePageCheckoutSubmitHandler) {
+            throw new \RuntimeException('submit handler not configured');
+        }
+
+        return $this->submitHandler;
+    }
+
+    protected function buildTechnicalErrorResponse(): array
+    {
+        return [
+            'success' => false,
+            'error' => 'technical-error',
+            'reload' => true,
+            'checkout_url' => '/commande',
+        ];
+    }
+}
diff --git a/tests/php/Unit/Controller/PaymentMethodsControllerTest.php b/tests/php/Unit/Controller/PaymentMethodsControllerTest.php
new file mode 100644
index 0000000..6ce7d0a
--- /dev/null
+++ b/tests/php/Unit/Controller/PaymentMethodsControllerTest.php
@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Controller;
+
+if (!defined('_DB_PREFIX_')) {
+    define('_DB_PREFIX_', 'ps_');
+}
+
+use PHPUnit\Framework\TestCase;
+
+class PaymentMethodsControllerTest extends TestCase
+{
+    public function testHandlePaymentMethodsReturnsTechnicalErrorWhenModuleIsDisabled(): void
+    {
+        $controller = new class extends \Ps_OnepagecheckoutPaymentMethodsModuleFrontController {
+            public function setTestContext(\Context $context): void
+            {
+                $this->context = $context;
+            }
+
+            public function __construct()
+            {
+            }
+
+            public function callHandleOpcRequest(): array
+            {
+                return $this->handleOpcRequest();
+            }
+
+            protected function buildTechnicalErrorResponse(): array
+            {
+                return ['success' => false, 'error' => 'technical-error'];
+            }
+        };
+        $controller->module = new class extends \Ps_Onepagecheckout {
+            public function __construct()
+            {
+            }
+
+            public function isOnePageCheckoutEnabled(): bool
+            {
+                return false;
+            }
+        };
+
+        self::assertSame('technical-error', $controller->callHandleOpcRequest()['error']);
+    }
+}
diff --git a/tests/php/Unit/Controller/SaveAddressControllerTest.php b/tests/php/Unit/Controller/SaveAddressControllerTest.php
new file mode 100644
index 0000000..e15b389
--- /dev/null
+++ b/tests/php/Unit/Controller/SaveAddressControllerTest.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Controller;
+
+if (!defined('_DB_PREFIX_')) {
+    define('_DB_PREFIX_', 'ps_');
+}
+
+use PHPUnit\Framework\TestCase;
+
+class SaveAddressControllerTest extends TestCase
+{
+    public function testHandleSaveAddressReturnsTechnicalErrorWhenModuleIsDisabled(): void
+    {
+        $controller = new class extends \Ps_OnepagecheckoutSaveAddressModuleFrontController {
+            public function __construct()
+            {
+            }
+
+            public function callHandleOpcRequest(): array
+            {
+                return $this->handleOpcRequest();
+            }
+
+            protected function buildTechnicalErrorResponse(): array
+            {
+                return ['success' => false, 'error' => 'technical-error'];
+            }
+        };
+        $controller->module = new class extends \Ps_Onepagecheckout {
+            public function __construct()
+            {
+            }
+
+            public function isOnePageCheckoutEnabled(): bool
+            {
+                return false;
+            }
+        };
+
+        self::assertSame('technical-error', $controller->callHandleOpcRequest()['error']);
+    }
+}
diff --git a/tests/php/Unit/Controller/SelectCarrierControllerTest.php b/tests/php/Unit/Controller/SelectCarrierControllerTest.php
new file mode 100644
index 0000000..fce16de
--- /dev/null
+++ b/tests/php/Unit/Controller/SelectCarrierControllerTest.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Controller;
+
+if (!defined('_DB_PREFIX_')) {
+    define('_DB_PREFIX_', 'ps_');
+}
+
+use PHPUnit\Framework\TestCase;
+
+class SelectCarrierControllerTest extends TestCase
+{
+    public function testHandleSelectCarrierReturnsTechnicalErrorWhenModuleIsDisabled(): void
+    {
+        $controller = new class extends \Ps_OnepagecheckoutSelectCarrierModuleFrontController {
+            public function __construct()
+            {
+            }
+
+            public function callHandleOpcRequest(): array
+            {
+                return $this->handleOpcRequest();
+            }
+
+            protected function buildTechnicalErrorResponse(): array
+            {
+                return ['success' => false, 'error' => 'technical-error'];
+            }
+        };
+        $controller->module = new class extends \Ps_Onepagecheckout {
+            public function __construct()
+            {
+            }
+
+            public function isOnePageCheckoutEnabled(): bool
+            {
+                return false;
+            }
+        };
+
+        self::assertSame('technical-error', $controller->callHandleOpcRequest()['error']);
+    }
+}
diff --git a/tests/php/Unit/Controller/SelectPaymentControllerTest.php b/tests/php/Unit/Controller/SelectPaymentControllerTest.php
new file mode 100644
index 0000000..f893ada
--- /dev/null
+++ b/tests/php/Unit/Controller/SelectPaymentControllerTest.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Controller;
+
+if (!defined('_DB_PREFIX_')) {
+    define('_DB_PREFIX_', 'ps_');
+}
+
+use PHPUnit\Framework\TestCase;
+
+class SelectPaymentControllerTest extends TestCase
+{
+    public function testHandleSelectPaymentReturnsTechnicalErrorWhenModuleIsDisabled(): void
+    {
+        $controller = new class extends \Ps_OnepagecheckoutSelectPaymentModuleFrontController {
+            public function __construct()
+            {
+            }
+
+            public function callHandleOpcRequest(): array
+            {
+                return $this->handleOpcRequest();
+            }
+
+            protected function buildTechnicalErrorResponse(): array
+            {
+                return ['success' => false, 'error' => 'technical-error'];
+            }
+        };
+        $controller->module = new class extends \Ps_Onepagecheckout {
+            public function __construct()
+            {
+            }
+
+            public function isOnePageCheckoutEnabled(): bool
+            {
+                return false;
+            }
+        };
+
+        self::assertSame('technical-error', $controller->callHandleOpcRequest()['error']);
+    }
+}
diff --git a/tests/php/Unit/Controller/StatesControllerTest.php b/tests/php/Unit/Controller/StatesControllerTest.php
new file mode 100644
index 0000000..4aa5a62
--- /dev/null
+++ b/tests/php/Unit/Controller/StatesControllerTest.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Controller;
+
+if (!defined('_DB_PREFIX_')) {
+    define('_DB_PREFIX_', 'ps_');
+}
+
+use PHPUnit\Framework\TestCase;
+
+class StatesControllerTest extends TestCase
+{
+    public function testHandleStatesReturnsTechnicalErrorWhenModuleIsDisabled(): void
+    {
+        $controller = new class extends \Ps_OnepagecheckoutStatesModuleFrontController {
+            public function __construct()
+            {
+            }
+
+            public function callHandleOpcRequest(): array
+            {
+                return $this->handleOpcRequest();
+            }
+
+            protected function buildTechnicalErrorResponse(): array
+            {
+                return ['success' => false, 'error' => 'technical-error'];
+            }
+        };
+        $controller->module = new class extends \Ps_Onepagecheckout {
+            public function __construct()
+            {
+            }
+
+            public function isOnePageCheckoutEnabled(): bool
+            {
+                return false;
+            }
+        };
+
+        self::assertSame('technical-error', $controller->callHandleOpcRequest()['error']);
+    }
+}
diff --git a/tests/php/Unit/Form/AddressFieldsFormatTraitTest.php b/tests/php/Unit/Form/AddressFieldsFormatTraitTest.php
index 9a8b711..5e8d4d3 100644
--- a/tests/php/Unit/Form/AddressFieldsFormatTraitTest.php
+++ b/tests/php/Unit/Form/AddressFieldsFormatTraitTest.php
@@ -17,16 +17,12 @@
 use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
 use PHPUnit\Framework\TestCase;
 use PrestaShop\Module\PsOnePageCheckout\Form\AddressFieldsFormatTrait;
+use Tests\Fixtures\CheckoutTestFixtures;
 
 #[RunTestsInSeparateProcesses]
 #[PreserveGlobalState(false)]
 class AddressFieldsFormatTraitTest extends TestCase
 {
-    protected function setUp(): void
-    {
-        $this->defineGlobalStubs();
-    }
-
     public function testItBuildsExpectedAddressFieldsFormatAndAppliesDefinitionMetadata(): void
     {
         \AddressFormat::$orderedFields = [
@@ -61,23 +57,15 @@ public function testItBuildsExpectedAddressFieldsFormatAndAppliesDefinitionMetad
             ],
         ];
 
-        $country = new \Country();
-        $country->id = 33;
-        $country->need_zip_code = true;
-        $country->zip_code_format = 'NNNNN';
-        $country->need_identification_number = true;
-        $country->contains_states = true;
-
-        $translator = new class {
-            public function trans(string $message, array $parameters = [], string $domain = ''): string
-            {
-                return $message;
-            }
-        };
-
-        $sut = new AddressFieldsFormatTraitHarness(
-            $country,
-            $translator,
+        $sut = $this->createHarness(
+            $this->createCountry([
+                'id' => 33,
+                'need_zip_code' => true,
+                'zip_code_format' => 'NNNNN',
+                'need_identification_number' => true,
+                'contains_states' => true,
+            ]),
+            CheckoutTestFixtures::translator(static fn (string $message): string => $message),
             [
                 ['id_country' => 33, 'name' => 'France'],
                 ['id_country' => 34, 'name' => 'Spain'],
@@ -122,17 +110,12 @@ public function testItKeepsAliasOptionalWhenAliasRequiredIsFalse(): void
         \AddressFormat::$orderedFields = [];
         \AddressFormat::$requiredFields = [];
 
-        $country = new \Country();
-        $country->id = 1;
-
-        $translator = new class {
-            public function trans(string $message, array $parameters = [], string $domain = ''): string
-            {
-                return $message;
-            }
-        };
-
-        $sut = new AddressFieldsFormatTraitHarness($country, $translator, [], []);
+        $sut = $this->createHarness(
+            $this->createCountry(['id' => 1]),
+            CheckoutTestFixtures::translator(static fn (string $message): string => $message),
+            [],
+            []
+        );
         $format = $sut->exposeGetAddressFieldsFormat('', false);
 
         self::assertArrayHasKey('alias', $format);
@@ -145,16 +128,12 @@ public function trans(string $message, array $parameters = [], string $domain =
      */
     public function testItReturnsExpectedFieldLabels(string $field, string $expected): void
     {
-        $country = new \Country();
-        $country->id = 1;
-        $translator = new class {
-            public function trans(string $message, array $parameters = [], string $domain = ''): string
-            {
-                return $message;
-            }
-        };
-
-        $sut = new AddressFieldsFormatTraitHarness($country, $translator, [], []);
+        $sut = $this->createHarness(
+            $this->createCountry(['id' => 1]),
+            CheckoutTestFixtures::translator(static fn (string $message): string => $message),
+            [],
+            []
+        );
 
         self::assertSame($expected, $sut->exposeGetFieldLabel($field));
     }
@@ -182,95 +161,25 @@ public static function provideFieldLabels(): iterable
         yield 'fallback' => ['custom_field', 'custom_field'];
     }
 
-    private function defineGlobalStubs(): void
-    {
-        if (!class_exists('FormField', false)) {
-            eval(<<<'PHP'
-class FormField
-{
-    public ?string $moduleName = null;
-    private string $name = '';
-    private string $type = 'text';
-    private bool $required = false;
-    private string $label = '';
-    private $value = null;
-    private array $availableValues = [];
-    private ?int $minLength = null;
-    private ?int $maxLength = null;
-    private array $constraints = [];
-
-    public function setName($name) { $this->name = (string) $name; return $this; }
-    public function getName() { return $this->name; }
-    public function setType($type) { $this->type = (string) $type; return $this; }
-    public function getType() { return $this->type; }
-    public function setRequired($required) { $this->required = (bool) $required; return $this; }
-    public function isRequired() { return $this->required; }
-    public function setLabel($label) { $this->label = (string) $label; return $this; }
-    public function getLabel() { return $this->label; }
-    public function setValue($value) { $this->value = $value; return $this; }
-    public function getValue() { return $this->value; }
-    public function addAvailableValue($value, $label = null) { $this->availableValues[$value] = $label ?? $value; return $this; }
-    public function getAvailableValues() { return $this->availableValues; }
-    public function setMinLength($minLength) { $this->minLength = (int) $minLength; return $this; }
-    public function getMinLength() { return $this->minLength; }
-    public function setMaxLength($maxLength) { $this->maxLength = (int) $maxLength; return $this; }
-    public function getMaxLength() { return $this->maxLength; }
-    public function addConstraint($constraint) { $this->constraints[] = $constraint; return $this; }
-    public function getConstraints() { return $this->constraints; }
-}
-PHP
-            );
-        }
-
-        if (!class_exists('Country', false)) {
-            eval(<<<'PHP'
-class Country
-{
-    public int $id = 0;
-    public bool $need_zip_code = false;
-    public string $zip_code_format = '';
-    public bool $need_identification_number = false;
-    public bool $contains_states = false;
-}
-PHP
-            );
-        }
-
-        if (!class_exists('AddressFormat', false)) {
-            eval(<<<'PHP'
-class AddressFormat
-{
-    public static array $orderedFields = [];
-    public static array $requiredFields = [];
-
-    public static function getOrderedAddressFields($idCountry = 0, $splitAll = false, $cleaned = false)
-    {
-        return self::$orderedFields;
-    }
-
-    public static function getFieldsRequired()
+    /**
+     * @param array<string, mixed> $overrides
+     */
+    private function createCountry(array $overrides): \Country
     {
-        return self::$requiredFields;
+        return CheckoutTestFixtures::country($overrides);
     }
-}
-PHP
-            );
-        }
-
-        if (!class_exists('State', false)) {
-            eval(<<<'PHP'
-class State
-{
-    public static array $statesByCountry = [];
 
-    public static function getStatesByIdCountry($idCountry, $active = false, $orderBy = null, $sort = 'ASC')
-    {
-        return self::$statesByCountry[(int) $idCountry] ?? [];
-    }
-}
-PHP
-            );
-        }
+    /**
+     * @param array<int, array<string, mixed>> $availableCountries
+     * @param array<string, array<string, mixed>> $definition
+     */
+    private function createHarness(
+        \Country $country,
+        object $translator,
+        array $availableCountries,
+        array $definition,
+    ): AddressFieldsFormatTraitHarness {
+        return new AddressFieldsFormatTraitHarness($country, $translator, $availableCountries, $definition);
     }
 }
 
diff --git a/tests/php/Unit/Form/AddressFormValidationTraitTest.php b/tests/php/Unit/Form/AddressFormValidationTraitTest.php
index b5184e5..73382fe 100644
--- a/tests/php/Unit/Form/AddressFormValidationTraitTest.php
+++ b/tests/php/Unit/Form/AddressFormValidationTraitTest.php
@@ -17,24 +17,21 @@
 use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
 use PHPUnit\Framework\TestCase;
 use PrestaShop\Module\PsOnePageCheckout\Form\AddressFormValidationTrait;
+use Tests\Fixtures\CheckoutTestFixtures;
 
 #[RunTestsInSeparateProcesses]
 #[PreserveGlobalState(false)]
 class AddressFormValidationTraitTest extends TestCase
 {
-    protected function setUp(): void
-    {
-        $this->defineGlobalStubs();
-    }
-
     public function testItFailsWhenDeliveryPostcodeIsInvalid(): void
     {
-        $sut = new AddressFormValidationTraitHarness($this->buildTranslator(), (object) ['id' => 1]);
+        $sut = $this->createHarness();
 
-        $deliveryCountry = new \Country();
-        $deliveryCountry->need_zip_code = true;
-        $deliveryCountry->zip_code_format = 'NNNNN';
-        $deliveryCountry->validZipCodes = ['75001'];
+        $deliveryCountry = $this->createCountry([
+            'need_zip_code' => true,
+            'zip_code_format' => 'NNNNN',
+            'validZipCodes' => ['75001'],
+        ]);
 
         $postcode = (new \FormField())
             ->setRequired(true)
@@ -48,12 +45,13 @@ public function testItFailsWhenDeliveryPostcodeIsInvalid(): void
 
     public function testItValidatesInvoicePostcodeAgainstInvoiceCountryField(): void
     {
-        $sut = new AddressFormValidationTraitHarness($this->buildTranslator(), (object) ['id' => 1]);
+        $sut = $this->createHarness();
 
-        $deliveryCountry = new \Country();
-        $deliveryCountry->need_zip_code = true;
-        $deliveryCountry->zip_code_format = 'NNNNN';
-        $deliveryCountry->validZipCodes = ['75001'];
+        $deliveryCountry = $this->createCountry([
+            'need_zip_code' => true,
+            'zip_code_format' => 'NNNNN',
+            'validZipCodes' => ['75001'],
+        ]);
 
         \Country::$registry[2] = [
             'need_zip_code' => true,
@@ -77,14 +75,39 @@ public function testItValidatesInvoicePostcodeAgainstInvoiceCountryField(): void
         self::assertNotEmpty($invoicePostcode->getErrors());
     }
 
+    public function testItValidatesInvoicePostcodeAgainstDeliveryCountryWhenNoInvoiceCountryIsProvided(): void
+    {
+        $sut = $this->createHarness();
+
+        $deliveryCountry = $this->createCountry([
+            'need_zip_code' => true,
+            'zip_code_format' => 'NNNNN',
+            'validZipCodes' => ['75001'],
+        ]);
+
+        $invoicePostcode = (new \FormField())
+            ->setRequired(true)
+            ->setValue('99999');
+
+        $isValid = $sut->exposeValidateAddressPostcode(
+            null,
+            $deliveryCountry,
+            $invoicePostcode
+        );
+
+        self::assertFalse($isValid);
+        self::assertNotEmpty($invoicePostcode->getErrors());
+    }
+
     public function testItSkipsInvoicePostcodeCheckWhenInvoiceCountryDoesNotNeedZipCode(): void
     {
-        $sut = new AddressFormValidationTraitHarness($this->buildTranslator(), (object) ['id' => 1]);
+        $sut = $this->createHarness();
 
-        $deliveryCountry = new \Country();
-        $deliveryCountry->need_zip_code = true;
-        $deliveryCountry->zip_code_format = 'NNNNN';
-        $deliveryCountry->validZipCodes = ['75001'];
+        $deliveryCountry = $this->createCountry([
+            'need_zip_code' => true,
+            'zip_code_format' => 'NNNNN',
+            'validZipCodes' => ['75001'],
+        ]);
 
         \Country::$registry[3] = [
             'need_zip_code' => false,
@@ -110,12 +133,13 @@ public function testItSkipsInvoicePostcodeCheckWhenInvoiceCountryDoesNotNeedZipC
 
     public function testItReturnsTrueWhenNoRequiredPostcodesAreProvided(): void
     {
-        $sut = new AddressFormValidationTraitHarness($this->buildTranslator(), (object) ['id' => 1]);
+        $sut = $this->createHarness();
 
-        $country = new \Country();
-        $country->need_zip_code = true;
-        $country->zip_code_format = 'NNNNN';
-        $country->validZipCodes = [];
+        $country = $this->createCountry([
+            'need_zip_code' => true,
+            'zip_code_format' => 'NNNNN',
+            'validZipCodes' => [],
+        ]);
 
         $deliveryPostcode = (new \FormField())
             ->setRequired(false)
@@ -133,7 +157,7 @@ public function testItReturnsTrueWhenNoRequiredPostcodesAreProvided(): void
 
     public function testItReturnsFalseWhenValidationHookReturnsFalse(): void
     {
-        $sut = new AddressFormValidationTraitHarness($this->buildTranslator(), (object) ['id' => 1]);
+        $sut = $this->createHarness();
         \Hook::$responses['actionValidateCustomerAddressForm'] = false;
 
         self::assertFalse($sut->exposeValidateAddressFormHook());
@@ -141,7 +165,7 @@ public function testItReturnsFalseWhenValidationHookReturnsFalse(): void
 
     public function testItReturnsTrueWhenValidationHookReturnsNull(): void
     {
-        $sut = new AddressFormValidationTraitHarness($this->buildTranslator(), (object) ['id' => 1]);
+        $sut = $this->createHarness();
         \Hook::$responses['actionValidateCustomerAddressForm'] = null;
 
         self::assertTrue($sut->exposeValidateAddressFormHook());
@@ -149,77 +173,20 @@ public function testItReturnsTrueWhenValidationHookReturnsNull(): void
 
     private function buildTranslator(): object
     {
-        return new class {
-            public function trans(string $message, array $parameters = [], string $domain = ''): string
-            {
-                return strtr($message, $parameters);
-            }
-        };
-    }
-
-    private function defineGlobalStubs(): void
-    {
-        if (!class_exists('FormField', false)) {
-            eval(<<<'PHP'
-class FormField
-{
-    private bool $required = false;
-    private $value = null;
-    private array $errors = [];
-
-    public function setRequired($required) { $this->required = (bool) $required; return $this; }
-    public function isRequired() { return $this->required; }
-    public function setValue($value) { $this->value = $value; return $this; }
-    public function getValue() { return $this->value; }
-    public function addError($error) { $this->errors[] = $error; return $this; }
-    public function getErrors() { return $this->errors; }
-}
-PHP
-            );
-        }
-
-        if (!class_exists('Country', false)) {
-            eval(<<<'PHP'
-class Country
-{
-    public static array $registry = [];
-    public bool $need_zip_code = false;
-    public string $zip_code_format = '';
-    public array $validZipCodes = [];
-
-    public function __construct(int $id = 0, int $idLang = 0)
-    {
-        if ($id > 0 && isset(self::$registry[$id])) {
-            $data = self::$registry[$id];
-            $this->need_zip_code = (bool) ($data['need_zip_code'] ?? false);
-            $this->zip_code_format = (string) ($data['zip_code_format'] ?? '');
-            $this->validZipCodes = (array) ($data['validZipCodes'] ?? []);
-        }
+        return CheckoutTestFixtures::translator();
     }
 
-    public function checkZipCode($postcode): bool
+    /**
+     * @param array<string, mixed> $overrides
+     */
+    private function createCountry(array $overrides): \Country
     {
-        return in_array((string) $postcode, $this->validZipCodes, true);
+        return CheckoutTestFixtures::country($overrides);
     }
-}
-PHP
-            );
-        }
-
-        if (!class_exists('Hook', false)) {
-            eval(<<<'PHP'
-class Hook
-{
-    public static array $responses = [];
 
-    public static function exec($hookName, $params = [])
+    private function createHarness(): AddressFormValidationTraitHarness
     {
-        return self::$responses[$hookName] ?? null;
-    }
-}
-PHP
-            );
-        }
+        return new AddressFormValidationTraitHarness($this->buildTranslator(), (object) ['id' => 1]);
     }
 }
 
diff --git a/tests/php/Unit/Form/BackOfficeConfigurationFormTest.php b/tests/php/Unit/Form/BackOfficeConfigurationFormTest.php
index 822841e..6d6759c 100644
--- a/tests/php/Unit/Form/BackOfficeConfigurationFormTest.php
+++ b/tests/php/Unit/Form/BackOfficeConfigurationFormTest.php
@@ -14,6 +14,34 @@
 
 class BackOfficeConfigurationFormTest extends TestCase
 {
+    /**
+     * @var array<string, mixed>
+     */
+    private array $backupPost = [];
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->backupPost = $_POST;
+
+        $context = \Context::getContext();
+        $context->link = new class {
+            public function getAdminLink(string $controller, bool $withToken = true, array $params = [], array $extraParams = []): string
+            {
+                return '/admin/index.php?controller=' . $controller;
+            }
+        };
+    }
+
+    protected function tearDown(): void
+    {
+        $_POST = $this->backupPost;
+        \Shop::setContext(\Shop::CONTEXT_ALL);
+
+        parent::tearDown();
+    }
+
     public function testItPersistsConfigurationValueWhenEnabled(): void
     {
         $form = new SpyBackOfficeConfigurationForm($this->createMock(\Module::class), 'PS_ONE_PAGE_CHECKOUT_ENABLED');
@@ -42,6 +70,21 @@ public function testItLoadsCurrentConfigurationValue(): void
         self::assertSame(1, $value);
         self::assertSame(1, $form->readConfigurationCalls);
     }
+
+    public function testItDoesNotPersistSubmittedValueOutsideSingleShopContext(): void
+    {
+        $_POST['submitPsOnePageCheckoutConfiguration'] = '1';
+        $_POST['PS_ONE_PAGE_CHECKOUT_ENABLED'] = '1';
+        \Shop::setContext(\Shop::CONTEXT_ALL);
+
+        $form = new SpyBackOfficeConfigurationForm($this->createMock(\Module::class), 'PS_ONE_PAGE_CHECKOUT_ENABLED');
+
+        $content = $form->renderBackOfficeConfiguration();
+
+        self::assertSame('', $content);
+        self::assertSame([], $form->updatedConfigurationValues);
+        self::assertSame(1, $form->redirectCalls);
+    }
 }
 
 class SpyBackOfficeConfigurationForm extends BackOfficeConfigurationForm
@@ -52,6 +95,7 @@ class SpyBackOfficeConfigurationForm extends BackOfficeConfigurationForm
     public array $updatedConfigurationValues = [];
 
     public int $readConfigurationCalls = 0;
+    public int $redirectCalls = 0;
 
     private int $nextReadValue = 0;
 
@@ -81,4 +125,9 @@ protected function readConfigurationValue(): int
 
         return $this->nextReadValue;
     }
+
+    protected function redirectToConfigurationForm(): void
+    {
+        ++$this->redirectCalls;
+    }
 }
diff --git a/tests/php/Unit/Form/OnePageCheckoutAddressFormatterTest.php b/tests/php/Unit/Form/OnePageCheckoutAddressFormatterTest.php
new file mode 100644
index 0000000..8c22b4a
--- /dev/null
+++ b/tests/php/Unit/Form/OnePageCheckoutAddressFormatterTest.php
@@ -0,0 +1,55 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Form;
+
+if (!defined('_DB_PREFIX_')) {
+    define('_DB_PREFIX_', 'ps_');
+}
+
+use PHPUnit\Framework\Attributes\PreserveGlobalState;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
+use PHPUnit\Framework\TestCase;
+use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutAddressFormatter;
+use Symfony\Contracts\Translation\TranslatorInterface;
+use Tests\Fixtures\CheckoutTestFixtures;
+
+#[RunTestsInSeparateProcesses]
+#[PreserveGlobalState(false)]
+class OnePageCheckoutAddressFormatterTest extends TestCase
+{
+    public function testItKeepsAliasOptionalInTheAddressModalFormat(): void
+    {
+        \Address::$definition = [
+            'fields' => [
+                'alias' => ['size' => 32],
+                'firstname' => ['size' => 64],
+                'id_country' => ['size' => 3],
+            ],
+        ];
+        \AddressFormat::$orderedFields = ['firstname', 'Country:name'];
+        \AddressFormat::$requiredFields = ['firstname', 'Country:name'];
+
+        $formatter = new OnePageCheckoutAddressFormatter(
+            CheckoutTestFixtures::country(['id' => 8, 'contains_states' => false]),
+            $this->createTranslator(),
+            [
+                ['id_country' => 8, 'name' => 'France'],
+            ]
+        );
+
+        $format = $formatter->getFormat();
+
+        self::assertArrayHasKey('alias', $format);
+        self::assertFalse($format['alias']->isRequired());
+    }
+
+    private function createTranslator(): TranslatorInterface
+    {
+        $translator = $this->createMock(TranslatorInterface::class);
+        $translator->method('trans')->willReturnArgument(0);
+
+        return $translator;
+    }
+}
diff --git a/tests/php/Unit/Form/OnePageCheckoutFormSpe7FinalSubmitTest.php b/tests/php/Unit/Form/OnePageCheckoutFormSpe7FinalSubmitTest.php
new file mode 100644
index 0000000..aaa7d80
--- /dev/null
+++ b/tests/php/Unit/Form/OnePageCheckoutFormSpe7FinalSubmitTest.php
@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Form;
+
+require_once __DIR__ . '/OnePageCheckoutFormTest.php';
+
+class OnePageCheckoutFormSpe7FinalSubmitTest extends OnePageCheckoutFormTest
+{
+}
diff --git a/tests/php/Unit/Form/OnePageCheckoutFormTest.php b/tests/php/Unit/Form/OnePageCheckoutFormTest.php
index 4f9cf3e..04ba4ae 100644
--- a/tests/php/Unit/Form/OnePageCheckoutFormTest.php
+++ b/tests/php/Unit/Form/OnePageCheckoutFormTest.php
@@ -18,6 +18,7 @@
 use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutForm;
 use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutFormatter;
 use Symfony\Contracts\Translation\TranslatorInterface;
+use Tests\Fixtures\CheckoutTestFixtures;
 
 class OnePageCheckoutFormTest extends TestCase
 {
@@ -27,7 +28,7 @@ class OnePageCheckoutFormTest extends TestCase
     private OnePageCheckoutFormatter|MockObject $formatter;
     private \CustomerPersister|MockObject $customerPersister;
     private \CustomerAddressPersister|MockObject $addressPersister;
-    private \Context|MockObject $context;
+    private LightweightContext $context;
 
     protected function setUp(): void
     {
@@ -39,18 +40,14 @@ protected function setUp(): void
 
         $this->formatter = $this->getMockBuilder(OnePageCheckoutFormatter::class)
             ->disableOriginalConstructor()
-            ->onlyMethods(['getFormat', 'getCountry', 'setCountry', 'setInvoiceCountry'])
+            ->onlyMethods(['getFormat', 'getCountry', 'setCountry', 'setInvoiceCountry', 'getFieldGroup'])
             ->getMock()
         ;
         $this->formatter
             ->method('getFormat')
             ->willReturnCallback([$this, 'getGuestInitFields'])
         ;
-        $defaultCountry = new class extends \Country {
-            public function __construct()
-            {
-            }
-        };
+        $defaultCountry = CheckoutTestFixtures::country();
         $defaultCountry->id = self::DEFAULT_COUNTRY_ID;
         $this->formatter
             ->method('getCountry')
@@ -64,6 +61,10 @@ public function __construct()
             ->method('setInvoiceCountry')
             ->willReturnSelf()
         ;
+        $this->formatter
+            ->method('getFieldGroup')
+            ->willReturnCallback([$this, 'getFieldGroupForTest'])
+        ;
 
         $this->customerPersister = $this->getMockBuilder(\CustomerPersister::class)
             ->disableOriginalConstructor()
@@ -75,7 +76,7 @@ public function __construct()
             ->getMock()
         ;
 
-        $this->context = $this->createMock(\Context::class);
+        $this->context = new LightweightContext();
         $this->context->customer = new LightweightCustomer();
     }
 
@@ -100,17 +101,13 @@ public function testItCreatesGuestCustomerWhenEmailAndRequiredCheckboxesAreValid
             ->willReturn(true)
         ;
 
-        $this->context
-            ->expects($this->never())
-            ->method('updateCustomer')
-        ;
-
         self::assertTrue($form->submitGuestInit($this->withDefaultCountry([
             'email' => 'guest@example.com',
             'psgdpr_privacy' => '1',
             'compliance_terms' => '1',
             'communication_channel' => 'email',
         ])));
+        self::assertNull($this->context->updatedCustomer);
         self::assertFalse($form->wasModuleValidationCalled());
     }
 
@@ -122,15 +119,11 @@ public function testItDoesNotCreateGuestCustomerWhenThirdPartyRequiredCheckboxIs
             ->expects($this->never())
             ->method('save')
         ;
-        $this->context
-            ->expects($this->never())
-            ->method('updateCustomer')
-        ;
-
         self::assertFalse($form->submitGuestInit($this->withDefaultCountry([
             'email' => 'guest@example.com',
             'psgdpr_privacy' => '1',
         ])));
+        self::assertNull($this->context->updatedCustomer);
 
         $errors = $form->getErrors();
         self::assertArrayHasKey('compliance_terms', $errors);
@@ -145,16 +138,12 @@ public function testItDoesNotCreateGuestCustomerWhenEmailIsInvalid(): void
             ->expects($this->never())
             ->method('save')
         ;
-        $this->context
-            ->expects($this->never())
-            ->method('updateCustomer')
-        ;
-
         self::assertFalse($form->submitGuestInit($this->withDefaultCountry([
             'email' => 'not-an-email',
             'psgdpr_privacy' => '1',
             'compliance_terms' => '1',
         ])));
+        self::assertNull($this->context->updatedCustomer);
 
         $errors = $form->getErrors();
         self::assertArrayHasKey('email', $errors);
@@ -170,17 +159,13 @@ public function testItAllowsGuestInitWhenRequiredNonCheckboxFieldIsMissing(): vo
             ->method('save')
             ->willReturn(true)
         ;
-        $this->context
-            ->expects($this->never())
-            ->method('updateCustomer')
-        ;
-
         self::assertTrue($form->submitGuestInit($this->withDefaultCountry([
             'email' => 'guest@example.com',
             'psgdpr_privacy' => '1',
             'compliance_terms' => '1',
             'communication_channel' => 'email',
         ])));
+        self::assertNull($this->context->updatedCustomer);
     }
 
     public function testItDoesNotCreateGuestCustomerWhenRequiredCheckboxIsExplicitlyZero(): void
@@ -191,16 +176,12 @@ public function testItDoesNotCreateGuestCustomerWhenRequiredCheckboxIsExplicitly
             ->expects($this->never())
             ->method('save')
         ;
-        $this->context
-            ->expects($this->never())
-            ->method('updateCustomer')
-        ;
-
         self::assertFalse($form->submitGuestInit($this->withDefaultCountry([
             'email' => 'guest@example.com',
             'psgdpr_privacy' => '1',
             'compliance_terms' => '0',
         ])));
+        self::assertNull($this->context->updatedCustomer);
 
         $errors = $form->getErrors();
         self::assertArrayHasKey('compliance_terms', $errors);
@@ -224,6 +205,7 @@ public function testGuestInitDoesNotCallModuleCustomerValidation(): void
             'email' => 'guest-no-module-validation@example.com',
             'psgdpr_privacy' => '1',
             'compliance_terms' => '1',
+            'communication_channel' => 'email',
         ])));
         self::assertFalse($form->wasModuleValidationCalled());
         self::assertEmpty($form->getField('compliance_note')->getErrors());
@@ -245,17 +227,13 @@ public function testItReturnsPersisterErrorsWhenGuestSaveFails(): void
                 'email' => ['Unable to save guest customer'],
             ])
         ;
-        $this->context
-            ->expects($this->never())
-            ->method('updateCustomer')
-        ;
-
         self::assertFalse($form->submitGuestInit($this->withDefaultCountry([
             'email' => 'guest@example.com',
             'psgdpr_privacy' => '1',
             'compliance_terms' => '1',
             'communication_channel' => 'email',
         ])));
+        self::assertNull($this->context->updatedCustomer);
     }
 
     public function testItDoesNotCreateGuestCustomerWhenRequiredRadioConsentIsMissing(): void
@@ -263,12 +241,11 @@ public function testItDoesNotCreateGuestCustomerWhenRequiredRadioConsentIsMissin
         $form = $this->createForm();
 
         $this->customerPersister
-            ->expects($this->once())
+            ->expects($this->never())
             ->method('save')
-            ->willReturn(true)
         ;
 
-        self::assertTrue($form->submitGuestInit($this->withDefaultCountry([
+        self::assertFalse($form->submitGuestInit($this->withDefaultCountry([
             'email' => 'guest-radio-missing@example.com',
             'psgdpr_privacy' => '1',
             'compliance_terms' => '1',
@@ -277,7 +254,7 @@ public function testItDoesNotCreateGuestCustomerWhenRequiredRadioConsentIsMissin
 
         $errors = $form->getErrors();
         self::assertArrayHasKey('communication_channel', $errors);
-        self::assertEmpty($errors['communication_channel']);
+        self::assertNotEmpty($errors['communication_channel']);
     }
 
     public function testGuestInitIgnoresRequiredAddressConsentFields(): void
@@ -295,6 +272,7 @@ public function testGuestInitIgnoresRequiredAddressConsentFields(): void
             'psgdpr_privacy' => '1',
             'compliance_terms' => '1',
             'compliance_note' => 'Ready',
+            'communication_channel' => 'email',
             'marketing_preferences' => '0',
         ])));
     }
@@ -314,6 +292,7 @@ public function testGuestInitIgnoresFinalSubmitVeto(): void
             'psgdpr_privacy' => '1',
             'compliance_terms' => '1',
             'compliance_note' => 'Ready',
+            'communication_channel' => 'email',
         ])));
     }
 
@@ -367,6 +346,29 @@ public function testItKeepsRealNamesForGuestWhenFillingFromCustomer(): void
 
     public function testItSeparatesTemplateVariablesByBusinessOrigin(): void
     {
+        $customerProbeText = (new \FormField())
+            ->setName('opcinvariantprobe_customer_text')
+            ->setType('text');
+        $customerProbeSelect = (new \FormField())
+            ->setName('opcinvariantprobe_customer_select')
+            ->setType('select');
+
+        $customerProbeTextarea = (new \FormField())
+            ->setName('opcinvariantprobe_customer_textarea')
+            ->setType('textarea');
+
+        $customerProbeCheckbox = (new \FormField())
+            ->setName('opcinvariantprobe_customer_checkbox')
+            ->setType('checkbox');
+
+        $customerProbeRadio = (new \FormField())
+            ->setName('opcinvariantprobe_customer_radio')
+            ->setType('radio-buttons');
+
+        $addressProbeCheckbox = (new \FormField())
+            ->setName('opcinvariantprobe_address_checkbox')
+            ->setType('checkbox');
+
         $form = $this->createForm();
         $form->setFormFieldsForTest([
             'email' => (new \FormField())
@@ -375,27 +377,15 @@ public function testItSeparatesTemplateVariablesByBusinessOrigin(): void
             'optin' => (new \FormField())
                 ->setName('optin')
                 ->setType('checkbox'),
-            'customer_probe_text' => (new \FormField())
-                ->setName('opcinvariantprobe_customer_text')
-                ->setType('text'),
-            'customer_probe_select' => (new \FormField())
-                ->setName('opcinvariantprobe_customer_select')
-                ->setType('select'),
-            'customer_probe_textarea' => (new \FormField())
-                ->setName('opcinvariantprobe_customer_textarea')
-                ->setType('textarea'),
-            'customer_probe_checkbox' => (new \FormField())
-                ->setName('opcinvariantprobe_customer_checkbox')
-                ->setType('checkbox'),
-            'customer_probe_radio' => (new \FormField())
-                ->setName('opcinvariantprobe_customer_radio')
-                ->setType('radio-buttons'),
+            'customer_probe_text' => $customerProbeText,
+            'customer_probe_select' => $customerProbeSelect,
+            'customer_probe_textarea' => $customerProbeTextarea,
+            'customer_probe_checkbox' => $customerProbeCheckbox,
+            'customer_probe_radio' => $customerProbeRadio,
             'firstname' => (new \FormField())
                 ->setName('firstname')
                 ->setType('text'),
-            'opcinvariantprobe_address_checkbox' => (new \FormField())
-                ->setName('opcinvariantprobe_address_checkbox')
-                ->setType('checkbox'),
+            'opcinvariantprobe_address_checkbox' => $addressProbeCheckbox,
             'invoice_address1' => (new \FormField())
                 ->setName('invoice_address1')
                 ->setType('text'),
@@ -426,17 +416,22 @@ public function testItSeparatesTemplateVariablesByBusinessOrigin(): void
             ],
             array_keys($templateVariables['formFields'])
         );
-        self::assertArrayNotHasKey('contactFields', $templateVariables);
-        self::assertArrayNotHasKey('additionalCustomerFields', $templateVariables);
-        self::assertArrayNotHasKey('useSameAddressField', $templateVariables);
-        self::assertArrayNotHasKey('deliveryFields', $templateVariables);
-        self::assertArrayNotHasKey('invoiceFields', $templateVariables);
-        self::assertArrayNotHasKey('invoiceMetaFields', $templateVariables);
+        self::assertArrayHasKey('contactFields', $templateVariables);
+        self::assertArrayHasKey('additionalCustomerFields', $templateVariables);
+        self::assertArrayHasKey('customer', $templateVariables);
+        self::assertArrayHasKey('useSameAddressField', $templateVariables);
+        self::assertArrayHasKey('deliveryFields', $templateVariables);
+        self::assertArrayHasKey('invoiceFields', $templateVariables);
+        self::assertArrayHasKey('invoiceMetaFields', $templateVariables);
+        self::assertArrayHasKey('token', $templateVariables);
+        self::assertArrayHasKey('addresses', $templateVariables['customer']);
         self::assertSame('email', $templateVariables['formFields']['email']['name']);
-        self::assertSame('opcinvariantprobe_customer_text', $templateVariables['formFields']['customer_probe_text']['name']);
+        self::assertSame('email', $templateVariables['contactFields']['email']['name']);
+        self::assertSame('opcinvariantprobe_customer_text', $templateVariables['additionalCustomerFields']['customer_probe_text']['name']);
         self::assertSame('use_same_address', $templateVariables['formFields']['use_same_address']['name']);
-        self::assertSame('invoice_address1', $templateVariables['formFields']['invoice_address1']['name']);
-        self::assertSame('id_address_invoice', $templateVariables['formFields']['id_address_invoice']['name']);
+        self::assertSame('firstname', $templateVariables['deliveryFields']['firstname']['name']);
+        self::assertSame('invoice_address1', $templateVariables['invoiceFields']['invoice_address1']['name']);
+        self::assertSame('id_address_invoice', $templateVariables['invoiceMetaFields']['id_address_invoice']['name']);
     }
 
     public function testSubmitPersistsDeliveryAndInvoiceAddressesWhenUseSameAddressIsDisabled(): void
@@ -445,7 +440,7 @@ public function testSubmitPersistsDeliveryAndInvoiceAddressesWhenUseSameAddressI
         $form->forceValidateResult(true);
 
         $this->context->cart = new LightweightCart();
-        $this->context->cart->id = 0;
+        $this->context->cart->id = -1;
 
         $this->customerPersister
             ->expects($this->once())
@@ -457,14 +452,6 @@ public function testSubmitPersistsDeliveryAndInvoiceAddressesWhenUseSameAddressI
             })
         ;
 
-        $this->context
-            ->expects($this->once())
-            ->method('updateCustomer')
-            ->with($this->callback(static function (\Customer $customer): bool {
-                return (int) $customer->id === 42;
-            }))
-        ;
-
         $savedAddresses = [];
         $this->addressPersister
             ->expects($this->exactly(2))
@@ -498,6 +485,8 @@ public function testSubmitPersistsDeliveryAndInvoiceAddressesWhenUseSameAddressI
             'id_address_delivery' => 101,
             'id_address_invoice' => 202,
         ], $result);
+        self::assertInstanceOf(\Customer::class, $this->context->updatedCustomer);
+        self::assertSame(42, (int) $this->context->updatedCustomer->id);
         self::assertCount(2, $savedAddresses);
         self::assertSame('John', (string) $savedAddresses[0]->firstname);
         self::assertSame('Doe', (string) $savedAddresses[0]->lastname);
@@ -513,7 +502,7 @@ public function testSubmitPersistsOnlyDeliveryAddressWhenUseSameAddressIsEnabled
         $form->forceValidateResult(true);
 
         $this->context->cart = new LightweightCart();
-        $this->context->cart->id = 0;
+        $this->context->cart->id = -1;
 
         $this->customerPersister
             ->expects($this->once())
@@ -525,11 +514,6 @@ public function testSubmitPersistsOnlyDeliveryAddressWhenUseSameAddressIsEnabled
             })
         ;
 
-        $this->context
-            ->expects($this->once())
-            ->method('updateCustomer')
-        ;
-
         $this->addressPersister
             ->expects($this->once())
             ->method('save')
@@ -556,6 +540,156 @@ public function testSubmitPersistsOnlyDeliveryAddressWhenUseSameAddressIsEnabled
             'id_address_delivery' => 303,
             'id_address_invoice' => 303,
         ], $result);
+        self::assertInstanceOf(\Customer::class, $this->context->updatedCustomer);
+        self::assertSame(43, (int) $this->context->updatedCustomer->id);
+    }
+
+    public function testSubmitUsesConnectedCustomerEmailWhenCheckoutPostOmitsIt(): void
+    {
+        $form = $this->createSubmitForm();
+        $form->forceValidateResult(true);
+
+        $this->context->customer = new LightweightCustomer();
+        $this->context->customer->id = 77;
+        $this->context->customer->is_guest = 0;
+        $this->context->customer->email = 'registered@example.com';
+        $this->context->cart = new LightweightCart();
+        $this->context->cart->id = -1;
+        $this->context->cart->id_customer = 77;
+
+        $this->customerPersister
+            ->expects($this->never())
+            ->method('save')
+        ;
+
+        $this->addressPersister
+            ->expects($this->once())
+            ->method('save')
+            ->willReturnCallback(static function (\Address $address): bool {
+                $address->id = 404;
+
+                return true;
+            })
+        ;
+
+        $form->fillWith($this->withDefaultCountry([
+            'firstname' => 'Spec',
+            'lastname' => 'FortyTwo',
+            'address1' => '4 Registered street',
+            'city' => 'Nantes',
+            'postcode' => '44000',
+            'psgdpr_privacy' => '1',
+            'compliance_terms' => '1',
+            'communication_channel' => 'email',
+            'use_same_address' => '1',
+        ]));
+        self::assertSame('registered@example.com', (string) $form->getValue('email'));
+
+        $result = $form->submit();
+
+        self::assertSame([
+            'id_address_delivery' => 404,
+            'id_address_invoice' => 404,
+        ], $result);
+        self::assertSame('registered@example.com', (string) $form->getValue('email'));
+    }
+
+    public function testGetAddressUsesSelectedSavedDeliveryAddressIdFromDeliveryRadioPost(): void
+    {
+        $form = $this->createSubmitForm();
+
+        $previousPost = $_POST ?? [];
+        $previousRequest = $_REQUEST ?? [];
+
+        $_POST['id_address_delivery'] = '505';
+        $_REQUEST['id_address_delivery'] = '505';
+
+        try {
+            $form->fillWith($this->withDefaultCountry([
+                'firstname' => 'Saved',
+                'lastname' => 'Address',
+                'address1' => '5 Existing street',
+                'city' => 'Nantes',
+                'postcode' => '44000',
+                'psgdpr_privacy' => '1',
+                'compliance_terms' => '1',
+                'communication_channel' => 'email',
+                'use_same_address' => '1',
+            ]));
+            $address = $form->getAddress();
+        } finally {
+            $_POST = $previousPost;
+            $_REQUEST = $previousRequest;
+        }
+
+        self::assertSame(505, (int) $address->id);
+    }
+
+    public function testFillWithKeepsSelectedDeliveryAndInvoiceCountriesWithoutManualOverride(): void
+    {
+        $language = CheckoutTestFixtures::language(1);
+
+        $formatter = $this->getMockBuilder(OnePageCheckoutFormatter::class)
+            ->disableOriginalConstructor()
+            ->onlyMethods(['getFormat', 'getCountry', 'setCountry', 'setInvoiceCountry'])
+            ->getMock()
+        ;
+
+        $formatter
+            ->method('getFormat')
+            ->willReturn([
+                'id_country' => (new \FormField())
+                    ->setName('id_country')
+                    ->setType('select')
+                    ->setRequired(true)
+                    ->setAvailableValues([
+                        ['id' => 8, 'label' => 'France'],
+                        ['id' => 21, 'label' => 'Belgium'],
+                    ]),
+                'invoice_id_country' => (new \FormField())
+                    ->setName('invoice_id_country')
+                    ->setType('select')
+                    ->setRequired(false)
+                    ->setAvailableValues([
+                        ['id' => 8, 'label' => 'France'],
+                        ['id' => 21, 'label' => 'Belgium'],
+                    ]),
+            ])
+        ;
+
+        $defaultCountry = CheckoutTestFixtures::country();
+        $defaultCountry->id = self::DEFAULT_COUNTRY_ID;
+
+        $formatter
+            ->method('getCountry')
+            ->willReturn($defaultCountry)
+        ;
+        $formatter
+            ->method('setCountry')
+            ->willReturnSelf()
+        ;
+        $formatter
+            ->method('setInvoiceCountry')
+            ->willReturnSelf()
+        ;
+
+        $form = new TestableOnePageCheckoutForm(
+            $this->createMock(\Smarty::class),
+            $this->context,
+            $language,
+            $this->translator,
+            $formatter,
+            $this->customerPersister,
+            $this->addressPersister
+        );
+
+        $form->fillWith([
+            'id_country' => '21',
+            'invoice_id_country' => '21',
+        ]);
+
+        self::assertSame('21', (string) $form->getValue('id_country'));
+        self::assertSame('21', (string) $form->getValue('invoice_id_country'));
     }
 
     /**
@@ -702,12 +836,7 @@ public function getSubmitFields(): array
 
     private function createForm(): OnePageCheckoutForm
     {
-        $language = new class extends \Language {
-            public function __construct()
-            {
-            }
-        };
-        $language->id = 1;
+        $language = CheckoutTestFixtures::language(1);
 
         return new TestableOnePageCheckoutForm(
             $this->createMock(\Smarty::class),
@@ -722,16 +851,12 @@ public function __construct()
 
     private function createSubmitForm(): OnePageCheckoutForm
     {
-        $language = new class extends \Language {
-            public function __construct()
-            {
-            }
-        };
+        $language = CheckoutTestFixtures::language();
         $language->id = 1;
 
         $submitFormatter = $this->getMockBuilder(OnePageCheckoutFormatter::class)
             ->disableOriginalConstructor()
-            ->onlyMethods(['getFormat', 'getCountry', 'setCountry', 'setInvoiceCountry'])
+            ->onlyMethods(['getFormat', 'getCountry', 'setCountry', 'setInvoiceCountry', 'getFieldGroup'])
             ->getMock()
         ;
         $submitFormatter
@@ -739,11 +864,7 @@ public function __construct()
             ->willReturn($this->getSubmitFields())
         ;
 
-        $defaultCountry = new class extends \Country {
-            public function __construct()
-            {
-            }
-        };
+        $defaultCountry = CheckoutTestFixtures::country();
         $defaultCountry->id = self::DEFAULT_COUNTRY_ID;
 
         $submitFormatter
@@ -758,6 +879,10 @@ public function __construct()
             ->method('setInvoiceCountry')
             ->willReturnSelf()
         ;
+        $submitFormatter
+            ->method('getFieldGroup')
+            ->willReturnCallback([$this, 'getFieldGroupForTest'])
+        ;
 
         return new TestableOnePageCheckoutForm(
             $this->createMock(\Smarty::class),
@@ -770,6 +895,13 @@ public function __construct()
         );
     }
 
+    public function getFieldGroupForTest(string $key): ?string
+    {
+        return in_array($key, ['compliance_terms', 'compliance_note', 'communication_channel', 'newsletter_optin'], true)
+            ? OnePageCheckoutFormatter::FIELD_GROUP_CUSTOMER
+            : null;
+    }
+
     /**
      * @param array<string, mixed> $params
      *
@@ -869,6 +1001,11 @@ class LightweightCustomer extends \Customer
     public function __construct()
     {
     }
+
+    public function isGuest(): bool
+    {
+        return (bool) $this->is_guest;
+    }
 }
 
 class LightweightCart extends \Cart
@@ -877,3 +1014,19 @@ public function __construct()
     {
     }
 }
+
+class LightweightContext extends \Context
+{
+    public ?\Customer $updatedCustomer = null;
+
+    public function __construct()
+    {
+        $this->cart = new LightweightCart();
+    }
+
+    public function updateCustomer(\Customer $customer): void
+    {
+        $this->updatedCustomer = $customer;
+        $this->customer = $customer;
+    }
+}
diff --git a/tests/php/Unit/Form/OnePageCheckoutFormatterTest.php b/tests/php/Unit/Form/OnePageCheckoutFormatterTest.php
index 5c79a16..38a98aa 100644
--- a/tests/php/Unit/Form/OnePageCheckoutFormatterTest.php
+++ b/tests/php/Unit/Form/OnePageCheckoutFormatterTest.php
@@ -18,18 +18,16 @@
 use PHPUnit\Framework\TestCase;
 use PrestaShop\Module\PsOnePageCheckout\Form\OnePageCheckoutFormatter;
 use Symfony\Contracts\Translation\TranslatorInterface;
+use Tests\Fixtures\CheckoutTestFixtures;
 
 #[RunTestsInSeparateProcesses]
 #[PreserveGlobalState(false)]
 class OnePageCheckoutFormatterTest extends TestCase
 {
-    protected function setUp(): void
-    {
-        $this->defineGlobalStubs();
-    }
-
     public function testItBuildsExpectedFormatWhenOptinHooksAndInvoiceCountryAreConfigured(): void
     {
+        \Context::getContext()->customer = CheckoutTestFixtures::customer([], true);
+
         \Address::$definition = [
             'fields' => [
                 'firstname' => ['validate' => 'isName', 'size' => 64],
@@ -69,24 +67,26 @@ public function testItBuildsExpectedFormatWhenOptinHooksAndInvoiceCountryAreConf
             'broken' => 123,
         ];
 
-        $deliveryCountry = new \Country();
-        $deliveryCountry->id = 33;
-        $deliveryCountry->need_zip_code = true;
-        $deliveryCountry->zip_code_format = 'NNNNN';
-        $deliveryCountry->need_identification_number = true;
-        $deliveryCountry->contains_states = true;
-
-        $invoiceCountry = new \Country();
-        $invoiceCountry->id = 44;
-        $invoiceCountry->need_zip_code = true;
-        $invoiceCountry->zip_code_format = 'NNNN';
-        $invoiceCountry->need_identification_number = true;
-        $invoiceCountry->contains_states = true;
+        $deliveryCountry = $this->createCountry([
+            'id' => 33,
+            'need_zip_code' => true,
+            'zip_code_format' => 'NNNNN',
+            'need_identification_number' => true,
+            'contains_states' => true,
+        ]);
+
+        $invoiceCountry = $this->createCountry([
+            'id' => 44,
+            'need_zip_code' => true,
+            'zip_code_format' => 'NNNN',
+            'need_identification_number' => true,
+            'contains_states' => true,
+        ]);
 
         $translator = $this->createMock(TranslatorInterface::class);
         $translator->method('trans')->willReturnArgument(0);
 
-        $formatter = new OnePageCheckoutFormatter(
+        $formatter = $this->createFormatter(
             $deliveryCountry,
             $translator,
             [
@@ -106,11 +106,13 @@ public function testItBuildsExpectedFormatWhenOptinHooksAndInvoiceCountryAreConf
         self::assertTrue($format['optin']->isRequired());
         self::assertArrayHasKey('use_same_address', $format);
         self::assertTrue($format['use_same_address']->getValue());
+        self::assertArrayHasKey('id_address_delivery', $format);
         self::assertArrayHasKey('id_address_invoice', $format);
+        self::assertArrayNotHasKey('id_address', $format);
         self::assertArrayHasKey('alias', $format);
         self::assertArrayHasKey('invoice_alias', $format);
-        self::assertTrue($format['alias']->isRequired());
-        self::assertTrue($format['invoice_alias']->isRequired());
+        self::assertFalse($format['alias']->isRequired());
+        self::assertFalse($format['invoice_alias']->isRequired());
         self::assertSame(33, $format['id_country']->getValue());
         self::assertSame(44, $format['invoice_id_country']->getValue());
         self::assertSame([33 => 'France', 44 => 'Belgium'], $format['id_country']->getAvailableValues());
@@ -136,6 +138,8 @@ public function testItBuildsExpectedFormatWhenOptinHooksAndInvoiceCountryAreConf
 
     public function testItBuildsFormatWithoutOptinAndUsesDeliveryCountryForInvoiceWhenInvoiceCountryIsNotSet(): void
     {
+        \Context::getContext()->customer = CheckoutTestFixtures::customer([], false);
+
         \Address::$definition = [
             'fields' => [
                 'firstname' => ['validate' => 'isName', 'size' => 64],
@@ -150,14 +154,15 @@ public function testItBuildsFormatWithoutOptinAndUsesDeliveryCountryForInvoiceWh
         \Hook::$responses['additionalCustomerFormFields'] = [];
         \Hook::$responses['additionalCustomerAddressFields'] = [];
 
-        $deliveryCountry = new \Country();
-        $deliveryCountry->id = 99;
-        $deliveryCountry->contains_states = false;
+        $deliveryCountry = $this->createCountry([
+            'id' => 99,
+            'contains_states' => false,
+        ]);
 
         $translator = $this->createMock(TranslatorInterface::class);
         $translator->method('trans')->willReturnArgument(0);
 
-        $formatter = new OnePageCheckoutFormatter(
+        $formatter = $this->createFormatter(
             $deliveryCountry,
             $translator,
             [['id_country' => 99, 'name' => 'Portugal']]
@@ -166,6 +171,8 @@ public function testItBuildsFormatWithoutOptinAndUsesDeliveryCountryForInvoiceWh
         $format = $formatter->getFormat();
 
         self::assertArrayNotHasKey('optin', $format);
+        self::assertFalse($format['alias']->isRequired());
+        self::assertFalse($format['invoice_alias']->isRequired());
         self::assertSame(99, $format['id_country']->getValue());
         self::assertSame(99, $format['invoice_id_country']->getValue());
 
@@ -174,161 +181,22 @@ public function testItBuildsFormatWithoutOptinAndUsesDeliveryCountryForInvoiceWh
         self::assertSame('firstname', $getDefinitionKey->invoke($formatter, 'firstname'));
     }
 
-    private function defineGlobalStubs(): void
-    {
-        if (!interface_exists('FormFormatterInterface', false)) {
-            eval(<<<'PHP'
-interface FormFormatterInterface
-{
-    public function getFormat();
-}
-PHP
-            );
-        }
-
-        if (!class_exists('FormField', false)) {
-            eval(<<<'PHP'
-class FormField
-{
-    public ?string $moduleName = null;
-    private string $name = '';
-    private string $type = 'text';
-    private bool $required = false;
-    private $value = null;
-    private string $label = '';
-    private array $availableValues = [];
-    private ?int $minLength = null;
-    private ?int $maxLength = null;
-    private array $constraints = [];
-
-    public function setName($name) { $this->name = (string) $name; return $this; }
-    public function getName() { return $this->name; }
-    public function setType($type) { $this->type = (string) $type; return $this; }
-    public function getType() { return $this->type; }
-    public function setRequired($required) { $this->required = (bool) $required; return $this; }
-    public function isRequired() { return $this->required; }
-    public function setValue($value) { $this->value = $value; return $this; }
-    public function getValue() { return $this->value; }
-    public function setLabel($label) { $this->label = (string) $label; return $this; }
-    public function getLabel() { return $this->label; }
-    public function addAvailableValue($value, $label = null) { $this->availableValues[$value] = $label ?? $value; return $this; }
-    public function getAvailableValues() { return $this->availableValues; }
-    public function setMinLength($minLength) { $this->minLength = (int) $minLength; return $this; }
-    public function getMinLength() { return $this->minLength; }
-    public function setMaxLength($maxLength) { $this->maxLength = (int) $maxLength; return $this; }
-    public function getMaxLength() { return $this->maxLength; }
-    public function addConstraint($constraint) { $this->constraints[] = $constraint; return $this; }
-    public function getConstraints() { return $this->constraints; }
-}
-PHP
-            );
-        }
-
-        if (!class_exists('Country', false)) {
-            eval(<<<'PHP'
-class Country
-{
-    public int $id = 0;
-    public bool $need_zip_code = false;
-    public string $zip_code_format = '';
-    public bool $need_identification_number = false;
-    public bool $contains_states = false;
-}
-PHP
-            );
-        }
-
-        if (!class_exists('Address', false)) {
-            eval(<<<'PHP'
-class Address
-{
-    public static array $definition = ['fields' => []];
-}
-PHP
-            );
-        }
-
-        if (!class_exists('Customer', false)) {
-            eval(<<<'PHP'
-class Customer
-{
-    public static array $requiredFields = [];
-
-    public function isFieldRequired($fieldName)
-    {
-        return in_array($fieldName, self::$requiredFields, true);
-    }
-}
-PHP
-            );
-        }
-
-        if (!class_exists('Configuration', false)) {
-            eval(<<<'PHP'
-class Configuration
-{
-    public static array $values = [];
-
-    public static function get($key)
+    /**
+     * @param array<string, mixed> $overrides
+     */
+    private function createCountry(array $overrides): \Country
     {
-        return self::$values[$key] ?? false;
+        return CheckoutTestFixtures::country($overrides);
     }
-}
-PHP
-            );
-        }
-
-        if (!class_exists('AddressFormat', false)) {
-            eval(<<<'PHP'
-class AddressFormat
-{
-    public static array $orderedFields = [];
-    public static array $requiredFields = [];
-
-    public static function getOrderedAddressFields($idCountry = 0, $splitAll = false, $cleaned = false)
-    {
-        return self::$orderedFields;
-    }
-
-    public static function getFieldsRequired()
-    {
-        return self::$requiredFields;
-    }
-}
-PHP
-            );
-        }
 
-        if (!class_exists('State', false)) {
-            eval(<<<'PHP'
-class State
-{
-    public static array $statesByCountry = [];
-
-    public static function getStatesByIdCountry($idCountry, $active = false, $orderBy = null, $sort = 'ASC')
-    {
-        return self::$statesByCountry[(int) $idCountry] ?? [];
-    }
-}
-PHP
-            );
-        }
-
-        if (!class_exists('Hook', false)) {
-            eval(<<<'PHP'
-class Hook
-{
-    public static array $responses = [];
-
-    public static function exec($hookName, $hookArgs = [], $idModule = null, $arrayReturn = false)
-    {
-        $response = self::$responses[$hookName] ?? ($arrayReturn ? [] : null);
-
-        return $response;
-    }
-}
-PHP
-            );
-        }
+    /**
+     * @param array<int, array<string, mixed>> $availableCountries
+     */
+    private function createFormatter(
+        \Country $country,
+        TranslatorInterface $translator,
+        array $availableCountries,
+    ): OnePageCheckoutFormatter {
+        return new OnePageCheckoutFormatter($country, $translator, $availableCountries);
     }
 }
diff --git a/tests/php/Unit/Js/OpcAddressModalSpe54ContractTest.php b/tests/php/Unit/Js/OpcAddressModalSpe54ContractTest.php
new file mode 100644
index 0000000..452cdbe
--- /dev/null
+++ b/tests/php/Unit/Js/OpcAddressModalSpe54ContractTest.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Js;
+
+use PHPUnit\Framework\TestCase;
+
+class OpcAddressModalSpe54ContractTest extends TestCase
+{
+    public function testAddressModalScriptReferencesExpectedOpcEndpoints(): void
+    {
+        $script = (string) file_get_contents(_PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/views/js/opc-address-modal.js');
+
+        self::assertStringContainsString('addressesList', $script);
+        self::assertStringContainsString('states', $script);
+        self::assertStringContainsString('saveAddress', $script);
+        self::assertStringContainsString('deleteAddress', $script);
+        self::assertStringContainsString('updatedOpcAddressForm', $script);
+        self::assertStringContainsString("$(document).on('input change', MODAL_FIELD_SELECTOR", $script);
+        self::assertStringContainsString('const $trigger = $(event.relatedTarget);', $script);
+        self::assertStringContainsString("$(document).on('shown.bs.modal', MODAL_SELECTOR", $script);
+        self::assertStringContainsString('setModalFieldsDisabled($modal, false);', $script);
+        self::assertStringContainsString('const $modal = $(`#${DELETE_CONFIRM_MODAL_ID}`);', $script);
+        self::assertStringNotContainsString('ensureDeleteConfirmModal', $script);
+        self::assertStringNotContainsString('syncDeliveryMethodsContainerAddressId', $script);
+        self::assertStringNotContainsString('syncHiddenAddressIdsFromSavedSelections', $script);
+        self::assertStringNotContainsString('recoverStaleSavedAddressSelections', $script);
+        self::assertStringNotContainsString('`${MODAL_SELECTOR} input, ${MODAL_SELECTOR} select, ${MODAL_SELECTOR} textarea`', $script);
+        self::assertStringNotContainsString('window.confirm', $script);
+    }
+}
diff --git a/tests/php/Unit/Js/OpcJavascriptContractTest.php b/tests/php/Unit/Js/OpcJavascriptContractTest.php
index d5c690c..1e4f35a 100644
--- a/tests/php/Unit/Js/OpcJavascriptContractTest.php
+++ b/tests/php/Unit/Js/OpcJavascriptContractTest.php
@@ -13,15 +13,88 @@
 
 class OpcJavascriptContractTest extends TestCase
 {
+    public function testSharedOpcContractsExposeCentralizedEventsAndSelectors(): void
+    {
+        $events = (string) file_get_contents(_PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/views/js/events.js');
+        $selectors = (string) file_get_contents(_PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/views/js/selectors.js');
+
+        self::assertStringContainsString("opcCarrierSelected: 'opcCarrierSelected'", $events);
+        self::assertStringContainsString("opcPaymentMethodsUpdated: 'opcPaymentMethodsUpdated'", $events);
+        self::assertStringContainsString("updatedOpcAddressForm: 'updatedOpcAddressForm'", $events);
+        self::assertStringContainsString("opcSubmitFailed: 'opcSubmitFailed'", $events);
+        self::assertStringContainsString("deliveryMethods: '#opc-delivery-methods'", $selectors);
+        self::assertStringContainsString("paymentMethods: '#opc-payment-methods'", $selectors);
+        self::assertStringContainsString("checkoutFooter: '.one-page-checkout__footer'", $selectors);
+        self::assertStringContainsString("address: '#opc-address-modal, #modal-delivery, #modal-invoice'", $selectors);
+    }
+
+    public function testSubmitScriptEmitsHistoricalFinalSubmitEvent(): void
+    {
+        $script = (string) file_get_contents(_PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/views/js/opc-submit.js');
+        self::assertStringContainsString("import OPC_EVENTS from './events';", $script);
+        self::assertStringContainsString("import OPC_SELECTORS from './selectors';", $script);
+        self::assertStringContainsString("import {getConfiguredOpcUrl, normalizeErrorResponse, updatePayAmount} from './runtime/opc-runtime';", $script);
+        self::assertStringContainsString('prestashop.emit(OPC_EVENTS.opcFinalSubmitStarted)', $script);
+        self::assertStringContainsString('const OPC_FORM_ID_SELECTOR = OPC_SELECTORS.opc.form;', $script);
+        self::assertStringContainsString('const PAY_BUTTON_SELECTOR = OPC_SELECTORS.opc.payButton;', $script);
+        self::assertStringContainsString('prestashop.on(OPC_EVENTS.opcPaymentMethodsLoading', $script);
+        self::assertStringContainsString('prestashop.on(OPC_EVENTS.opcPaymentMethodsFailed', $script);
+        self::assertStringContainsString('const OPC_SUBMIT_URL_KEY = \'opcSubmit\';', $script);
+        self::assertStringContainsString('function ajaxCheckCartStillOrderable()', $script);
+        self::assertStringContainsString('HTMLFormElement.prototype.submit.call(innerForm)', $script);
+        self::assertStringContainsString('const optionId = paymentRadio.id;', $script);
+        self::assertStringContainsString('function bindScopedValidationListeners(form)', $script);
+        self::assertStringContainsString('bindChangeValidationListeners(form, DELIVERY_OPTION_SELECTOR', $script);
+        self::assertStringContainsString('bindChangeValidationListeners(paymentContainer, PAYMENT_OPTION_SELECTOR', $script);
+        self::assertStringNotContainsString("document.addEventListener('change'", $script);
+        self::assertStringNotContainsString("payload.set('submitOnePageCheckout', '1')", $script);
+        self::assertStringContainsString('window.location.href = response.checkout_url || window.prestashop.urls.pages.order;', $script);
+    }
+
     public function testGuestInitScriptUsesModuleRuntimeContract(): void
     {
         $script = (string) file_get_contents(_PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/views/js/opc-guest-init.js');
-        self::assertStringContainsString('window.ps_onepagecheckout', $script);
+        self::assertStringContainsString('import {getConfiguredOpcUrl}', $script);
+        self::assertStringContainsString("import OPC_EVENTS from './events';", $script);
+        self::assertStringContainsString("import OPC_SELECTORS from './selectors';", $script);
+        self::assertStringContainsString('getConfiguredOpcUrl(MODULE_GUEST_INIT_URL_KEY)', $script);
+        self::assertStringContainsString('prestashop.on(OPC_EVENTS.opcFinalSubmitStarted', $script);
+        self::assertStringContainsString('const OPC_CONTACT_SECTION_SELECTOR = OPC_SELECTORS.opc.contactSection;', $script);
+        self::assertStringNotContainsString('getOpcAddressContainer', $script);
     }
 
     public function testAddressFormScriptUsesModuleRuntimeContract(): void
     {
         $script = (string) file_get_contents(_PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/views/js/opc-address.js');
-        self::assertStringContainsString('window.ps_onepagecheckout', $script);
+        self::assertStringContainsString('import {getConfiguredOpcUrl}', $script);
+        self::assertStringContainsString("import OPC_EVENTS from './events';", $script);
+        self::assertStringContainsString("import OPC_SELECTORS from './selectors';", $script);
+        self::assertStringContainsString('getConfiguredOpcUrl(MODULE_ADDRESS_FORM_URL_KEY)', $script);
+        self::assertStringContainsString('prestashop.emit(OPC_EVENTS.opcDeliveryAddressUpdated', $script);
+        self::assertStringContainsString('prestashop.emit(OPC_EVENTS.opcBillingAddressUpdated', $script);
+    }
+
+    public function testPaymentScriptsUseModuleRuntimeContracts(): void
+    {
+        $listScript = (string) file_get_contents(_PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/views/js/opc-payment-list.js');
+        $selectScript = (string) file_get_contents(_PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/views/js/opc-payment-select.js');
+
+        self::assertStringContainsString("import OPC_EVENTS from './events';", $listScript);
+        self::assertStringContainsString("import OPC_SELECTORS from './selectors';", $listScript);
+        self::assertStringContainsString('paymentMethods', $listScript);
+        self::assertStringContainsString("prestashop.emit('handleError'", $listScript);
+        self::assertStringContainsString('prestashop.on(OPC_EVENTS.opcCarrierSelected', $listScript);
+        self::assertStringContainsString('prestashop.on(OPC_EVENTS.opcGuestInitSuccess', $listScript);
+        self::assertStringContainsString('prestashop.on(OPC_EVENTS.opcCarriersLoading', $listScript);
+        self::assertStringContainsString('prestashop.on(OPC_EVENTS.opcCarriersFailed', $listScript);
+        self::assertStringContainsString('fetchGeneration', $listScript);
+        self::assertStringNotContainsString("prestashop.on('opcCarriersUpdated'", $listScript);
+        self::assertStringNotContainsString("prestashop.on('opcDeliveryAddressUpdated'", $listScript);
+        self::assertStringContainsString("import OPC_EVENTS from './events';", $selectScript);
+        self::assertStringContainsString("import OPC_SELECTORS from './selectors';", $selectScript);
+        self::assertStringContainsString('selectPayment', $selectScript);
+        self::assertStringContainsString('payment_selection_key', $selectScript);
+        self::assertStringContainsString('selected_payment_selection_key', $selectScript);
+        self::assertStringContainsString('OPC_EVENTS.opcPaymentMethodSelected', $selectScript);
     }
 }
diff --git a/tests/php/Unit/Module/PsOnepagecheckoutModuleTest.php b/tests/php/Unit/Module/PsOnepagecheckoutModuleTest.php
index c4784d2..f801292 100644
--- a/tests/php/Unit/Module/PsOnepagecheckoutModuleTest.php
+++ b/tests/php/Unit/Module/PsOnepagecheckoutModuleTest.php
@@ -170,6 +170,15 @@ public function testHookActionFrontControllerSetMediaAssignsFlagAndRegistersAsse
         self::assertArrayHasKey('ps_onepagecheckout', $module->javascriptDefinitions[0]);
         self::assertNotEmpty($module->javascriptDefinitions[0]['ps_onepagecheckout']['urls']['guestInit']);
         self::assertNotEmpty($module->javascriptDefinitions[0]['ps_onepagecheckout']['urls']['addressForm']);
+        self::assertNotEmpty($module->javascriptDefinitions[0]['ps_onepagecheckout']['urls']['addressesList']);
+        self::assertNotEmpty($module->javascriptDefinitions[0]['ps_onepagecheckout']['urls']['states']);
+        self::assertNotEmpty($module->javascriptDefinitions[0]['ps_onepagecheckout']['urls']['saveAddress']);
+        self::assertNotEmpty($module->javascriptDefinitions[0]['ps_onepagecheckout']['urls']['deleteAddress']);
+        self::assertNotEmpty($module->javascriptDefinitions[0]['ps_onepagecheckout']['urls']['carriers']);
+        self::assertNotEmpty($module->javascriptDefinitions[0]['ps_onepagecheckout']['urls']['selectCarrier']);
+        self::assertNotEmpty($module->javascriptDefinitions[0]['ps_onepagecheckout']['urls']['paymentMethods']);
+        self::assertNotEmpty($module->javascriptDefinitions[0]['ps_onepagecheckout']['urls']['selectPayment']);
+        self::assertNotEmpty($module->javascriptDefinitions[0]['ps_onepagecheckout']['urls']['opcSubmit']);
     }
 
     public function testHookActionFrontControllerSetMediaAssignsFlagAndSkipsAssetsWhenDisabled(): void
@@ -271,6 +280,15 @@ public function registerHook($hookName, $shopList = null): bool
         return $this->registerHookResult;
     }
 
+    public function trans(
+        $id,
+        array $parameters = [],
+        $domain = null,
+        $locale = null,
+    ): string {
+        return (string) $id;
+    }
+
     protected function createCheckoutProcessBuilder(): OnePageCheckoutProcessBuilder
     {
         if ($this->checkoutProcessBuilder instanceof OnePageCheckoutProcessBuilder) {
diff --git a/tests/php/bootstrap-autoload.php b/tests/php/bootstrap-autoload.php
index 89857de..5fcca0e 100644
--- a/tests/php/bootstrap-autoload.php
+++ b/tests/php/bootstrap-autoload.php
@@ -39,6 +39,35 @@
 $loader->addClassMap([
     'Ps_Onepagecheckout' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/ps_onepagecheckout.php',
     'AdminPsOnePageCheckoutController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/admin/AdminPsOnePageCheckoutController.php',
-    'Ps_OnepagecheckoutGuestInitModuleFrontController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/front/GuestInit.php',
-    'Ps_OnepagecheckoutAddressFormModuleFrontController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/front/AddressForm.php',
+    'Ps_OnepagecheckoutGuestInitModuleFrontController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/front/guestinit.php',
+    'Ps_OnepagecheckoutAddressFormModuleFrontController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/front/addressform.php',
+    'Ps_OnepagecheckoutAddressesListModuleFrontController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/front/addresseslist.php',
+    'Ps_OnepagecheckoutStatesModuleFrontController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/front/states.php',
+    'Ps_OnepagecheckoutSaveAddressModuleFrontController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/front/saveaddress.php',
+    'Ps_OnepagecheckoutDeleteAddressModuleFrontController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/front/deleteaddress.php',
+    'Ps_OnepagecheckoutCarriersModuleFrontController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/front/carriers.php',
+    'Ps_OnepagecheckoutSelectCarrierModuleFrontController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/front/selectcarrier.php',
+    'Ps_OnepagecheckoutPaymentMethodsModuleFrontController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/front/paymentmethods.php',
+    'Ps_OnepagecheckoutSelectPaymentModuleFrontController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/front/selectpayment.php',
+    'Ps_OnepagecheckoutOpcSubmitModuleFrontController' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/controllers/front/opcsubmit.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\CheckoutAjaxResponse' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Shared/CheckoutAjaxResponse.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\CartPresenterHelper' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Shared/CartPresenterHelper.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\CheckoutSessionFactory' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Shared/CheckoutSessionFactory.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\CheckoutCustomerContextResolver' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Customer/CheckoutCustomerContextResolver.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\CheckoutCustomerTemplateBuilder' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Customer/CheckoutCustomerTemplateBuilder.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\OnePageCheckoutGuestInitHandler' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Customer/OnePageCheckoutGuestInitHandler.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\OnePageCheckoutAddressFormHandler' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Address/OnePageCheckoutAddressFormHandler.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\OnePageCheckoutAddressesListHandler' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Address/OnePageCheckoutAddressesListHandler.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\OnePageCheckoutSaveAddressHandler' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Address/OnePageCheckoutSaveAddressHandler.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\OnePageCheckoutDeleteAddressHandler' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Address/OnePageCheckoutDeleteAddressHandler.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\OnePageCheckoutStatesHandler' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Address/OnePageCheckoutStatesHandler.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\OpcTempAddress' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Address/OpcTempAddress.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\OnePageCheckoutCarriersHandler' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Carrier/OnePageCheckoutCarriersHandler.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\OnePageCheckoutSelectCarrierHandler' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Carrier/OnePageCheckoutSelectCarrierHandler.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\TempAddressCarrierSelectionStorage' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Carrier/TempAddressCarrierSelectionStorage.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\OnePageCheckoutPaymentMethodsHandler' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Payment/OnePageCheckoutPaymentMethodsHandler.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\OnePageCheckoutSelectPaymentHandler' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Payment/OnePageCheckoutSelectPaymentHandler.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\Submit\\OnePageCheckoutSubmitHandler' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Submit/OnePageCheckoutSubmitHandler.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\Submit\\OnePageCheckoutSubmitProcessor' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Submit/OnePageCheckoutSubmitProcessor.php',
+    'PrestaShop\\Module\\PsOnePageCheckout\\Checkout\\Ajax\\Submit\\OnePageCheckoutSubmitValidationStateStorage' => _PS_ROOT_DIR_ . '/modules/ps_onepagecheckout/src/Checkout/Ajax/Submit/OnePageCheckoutSubmitValidationStateStorage.php',
 ]);
diff --git a/tests/php/bootstrap-unit.php b/tests/php/bootstrap-unit.php
index 65467ae..952b6d9 100644
--- a/tests/php/bootstrap-unit.php
+++ b/tests/php/bootstrap-unit.php
@@ -1,5 +1,20 @@
 <?php
 
+use PrestaShop\PrestaShop\Adapter\AddressFactory;
+use PrestaShop\PrestaShop\Adapter\ServiceLocator;
+use PrestaShop\PrestaShop\Core\Foundation\IoC\Container;
+use Tests\PHP\Mocks\LegacyConfiguration;
+use Tests\PHP\Mocks\LegacyEntityMapper;
+
 require __DIR__ . '/../../../../tests/Unit/bootstrap.php';
 require_once __DIR__ . '/Mocks/bootstrap.php';
+require_once __DIR__ . '/Fixtures/LegacyFormStubs.php';
+require_once __DIR__ . '/Fixtures/CheckoutTestFixtures.php';
 require __DIR__ . '/bootstrap-autoload.php';
+
+$legacyTestContainer = new Container();
+$legacyTestContainer->bind('\\PrestaShop\\PrestaShop\\Adapter\\EntityMapper', new LegacyEntityMapper(), true);
+$legacyTestContainer->bind('\\PrestaShop\\PrestaShop\\Core\\ConfigurationInterface', new LegacyConfiguration(), true);
+$legacyTestContainer->bind('\\PrestaShop\\PrestaShop\\Adapter\\AddressFactory', new AddressFactory(), true);
+
+ServiceLocator::setServiceContainerInstance($legacyTestContainer);
diff --git a/views/js/events.js b/views/js/events.js
new file mode 100644
index 0000000..8cc7e25
--- /dev/null
+++ b/views/js/events.js
@@ -0,0 +1,26 @@
+const OPC_EVENTS = {
+  opcCarrierSelected: 'opcCarrierSelected',
+  opcCarriersUpdated: 'opcCarriersUpdated',
+  opcCarriersFailed: 'opcCarriersFailed',
+  opcCarriersLoading: 'opcCarriersLoading',
+  opcPaymentMethodsLoading: 'opcPaymentMethodsLoading',
+  opcPaymentMethodsUpdated: 'opcPaymentMethodsUpdated',
+  opcPaymentMethodsFailed: 'opcPaymentMethodsFailed',
+  opcPaymentMethodSelected: 'opcPaymentMethodSelected',
+  opcGuestInitSuccess: 'opcGuestInitSuccess',
+  opcFinalSubmitStarted: 'opcFinalSubmitStarted',
+  opcFormValidated: 'opcFormValidated',
+  opcBillingSectionToggled: 'opcBillingSectionToggled',
+  opcSubmitFailed: 'opcSubmitFailed',
+  opcDeliveryAddressUpdated: 'opcDeliveryAddressUpdated',
+  opcBillingAddressUpdated: 'opcBillingAddressUpdated',
+  opcDeliveryAddressSelected: 'opcDeliveryAddressSelected',
+  opcBillingAddressSelected: 'opcBillingAddressSelected',
+  opcCartSummaryBeforeUpdate: 'opcCartSummaryBeforeUpdate',
+  opcCartSummaryUpdated: 'opcCartSummaryUpdated',
+  updatedOpcAddressForm: 'updatedOpcAddressForm',
+  opcCarriersRetry: 'opcCarriersRetry',
+  opcPaymentMethodsRetry: 'opcPaymentMethodsRetry',
+};
+
+export default OPC_EVENTS;
diff --git a/views/js/opc-address-modal.js b/views/js/opc-address-modal.js
new file mode 100644
index 0000000..d10eea0
--- /dev/null
+++ b/views/js/opc-address-modal.js
@@ -0,0 +1,1138 @@
+import OPC_EVENTS from './events';
+import OPC_SELECTORS from './selectors';
+import {getConfiguredOpcUrl} from './runtime/opc-runtime';
+
+/**
+ * Copyright since 2007 PrestaShop SA and Contributors
+ * PrestaShop is an International Registered Trademark & Property of PrestaShop SA
+ */
+(function psOpcAddressModalRuntime() {
+const $ = window.$ || window.jQuery;
+const prestashop = window.prestashop || {};
+
+if (!$) {
+  return;
+}
+
+const MODAL_SELECTOR = OPC_SELECTORS.modals.address;
+const SAVE_SELECTOR = '#submit-address-modal, .js-opc-save-address';
+const COUNTRY_SELECTOR = '[name="id_country"], [name$="id_country"]';
+const STATE_SELECTOR = '[name="id_state"], [name$="id_state"]';
+const MODAL_SCOPES = MODAL_SELECTOR.split(',').map((selector) => selector.trim());
+const SAVE_TARGETS = SAVE_SELECTOR.split(',').map((selector) => selector.trim());
+const COUNTRY_TARGETS = COUNTRY_SELECTOR.split(',').map((selector) => selector.trim());
+const MODAL_SAVE_SELECTOR = MODAL_SCOPES.flatMap((modalSelector) => {
+  return SAVE_TARGETS.map((targetSelector) => `${modalSelector} ${targetSelector}`);
+}).join(', ');
+const MODAL_COUNTRY_SELECTOR = MODAL_SCOPES.flatMap((modalSelector) => {
+  return COUNTRY_TARGETS.map((targetSelector) => `${modalSelector} ${targetSelector}`);
+}).join(', ');
+const MODAL_FIELD_SELECTOR = MODAL_SCOPES.flatMap((modalSelector) => {
+  return ['input', 'select', 'textarea'].map((fieldSelector) => `${modalSelector} ${fieldSelector}`);
+}).join(', ');
+const URL_KEYS = {
+  addressesList: 'addressesList',
+  states: 'states',
+  saveAddress: 'saveAddress',
+  deleteAddress: 'deleteAddress',
+  addressForm: 'addressForm',
+};
+const OPC_ADDRESSES_SECTION_SELECTOR = OPC_SELECTORS.opc.addressesSection;
+const DELIVERY_SECTION_SELECTOR = OPC_SELECTORS.opc.deliverySection;
+const DELIVERY_FIELDS_SELECTOR = OPC_SELECTORS.opc.deliveryFields;
+const BILLING_SECTION_SELECTOR = OPC_SELECTORS.opc.billingSection;
+const BILLING_FIELDS_SELECTOR = OPC_SELECTORS.opc.billingFields;
+const DISABLED_BY_SAME_ADDRESS_ATTRIBUTE = 'data-opc-disabled-by-same-address';
+const SERVER_MANAGED_FIELDS = new Set([
+  'id_country',
+  'invoice_id_country',
+  'id_state',
+  'invoice_id_state',
+  'use_same_address',
+]);
+const NON_PRESERVABLE_FIELD_TYPES = new Set(['hidden', 'file', 'submit', 'button', 'image', 'reset']);
+
+const ADDRESS_FIELDS = [
+  'id_address',
+  'alias',
+  'firstname',
+  'lastname',
+  'company',
+  'vat_number',
+  'address1',
+  'address2',
+  'city',
+  'postcode',
+  'id_state',
+  'id_country',
+  'phone',
+];
+const FIELD_ERROR_CLASS = 'js-opc-field-error';
+const GLOBAL_ERROR_CLASS = 'js-opc-address-modal-error';
+const DELETE_CONFIRM_MODAL_ID = 'opc-delete-address-confirm-modal';
+const RESTORE_SELECTION_ID_ATTRIBUTE = 'data-opc-restore-address-id';
+const RESTORE_SELECTION_RADIO_NAME_ATTRIBUTE = 'data-opc-restore-radio-name';
+const SKIP_RESTORE_SELECTION_ATTRIBUTE = 'data-opc-skip-restore-selection';
+
+function isNonSubmittableField($field) {
+  return $field.is(':button, [type="button"], [type="submit"], [type="reset"], [type="image"], [type="file"]');
+}
+
+function getFieldType($field) {
+  return String($field.prop('type') || '').toLowerCase();
+}
+
+function isServerManagedField(name) {
+  return !name || SERVER_MANAGED_FIELDS.has(name);
+}
+
+function isClientPreservableField(name, $field) {
+  if (isServerManagedField(name)) {
+    return false;
+  }
+
+  return !NON_PRESERVABLE_FIELD_TYPES.has(getFieldType($field));
+}
+
+function preserveFieldValue(preservedFields, name, $field) {
+  const type = getFieldType($field);
+
+  if (type === 'checkbox') {
+    if (!Array.isArray(preservedFields[name])) {
+      preservedFields[name] = [];
+    }
+
+    if ($field.is(':checked')) {
+      preservedFields[name].push(String($field.val()));
+    }
+
+    return;
+  }
+
+  if (type === 'radio') {
+    if ($field.is(':checked')) {
+      preservedFields[name] = String($field.val());
+    }
+
+    return;
+  }
+
+  preservedFields[name] = $field.val();
+}
+
+function restoreFieldValue($field, preservedValue) {
+  const type = getFieldType($field);
+
+  if (typeof preservedValue === 'undefined') {
+    return;
+  }
+
+  if (type === 'checkbox') {
+    const checkedValues = Array.isArray(preservedValue) ? preservedValue : [];
+    $field.prop('checked', checkedValues.includes(String($field.val())));
+
+    return;
+  }
+
+  if (type === 'radio') {
+    $field.prop('checked', String($field.val()) === String(preservedValue));
+
+    return;
+  }
+
+  $field.val(preservedValue);
+}
+
+function preserveAddressesSectionFields($addressForm) {
+  const preservedFields = Object.create(null);
+
+  $addressForm.find('input, select, textarea').each((_, field) => {
+    const $field = $(field);
+    const name = String($field.prop('name') || '');
+
+    if (!isClientPreservableField(name, $field)) {
+      return;
+    }
+
+    preserveFieldValue(preservedFields, name, $field);
+  });
+
+  return preservedFields;
+}
+
+function restoreAddressesSectionFields($addressForm, preservedFields) {
+  $addressForm.find('input, select, textarea').each((_, field) => {
+    const $field = $(field);
+    const name = String($field.prop('name') || '');
+
+    if (!isClientPreservableField(name, $field)) {
+      return;
+    }
+
+    restoreFieldValue($field, preservedFields[name]);
+  });
+}
+
+function setModalFieldsDisabled($modal, disabled) {
+  $modal.find('input, select, textarea').each((_, field) => {
+    const $field = $(field);
+
+    if ($field.is('[type="hidden"]') || isNonSubmittableField($field)) {
+      return;
+    }
+
+    $field.prop('disabled', disabled);
+  });
+}
+
+function disableClosedModalFields() {
+  $(MODAL_SELECTOR).each((_, modal) => {
+    const $modal = $(modal);
+
+    if (!$modal.hasClass('show')) {
+      setModalFieldsDisabled($modal, true);
+    }
+  });
+}
+
+function retriggerCheckoutValidation() {
+  const form = document.querySelector(OPC_SELECTORS.opc.checkout);
+
+  if (!form) {
+    return;
+  }
+
+  form.dispatchEvent(new Event('change', {bubbles: true}));
+}
+
+function getModalField($modal, fieldName) {
+  const $exactField = $modal.find(`[name="${fieldName}"]`).first();
+  if ($exactField.length) {
+    return $exactField;
+  }
+
+  return $modal.find(`[name$="${fieldName}"]`).first();
+}
+
+function getAddressSection($addressForm, sectionSelector, fieldsSelector) {
+  const $fields = $addressForm.find(fieldsSelector).first();
+  if ($fields.length) {
+    return $fields;
+  }
+
+  return $addressForm.find(sectionSelector).first();
+}
+
+function getAddressSectionFieldValue($addressForm, sectionSelector, fieldsSelector, fieldName) {
+  const $section = getAddressSection($addressForm, sectionSelector, fieldsSelector);
+  if (!$section.length) {
+    return '';
+  }
+
+  const $field = $section.find(`[name="${fieldName}"]`).first();
+  if (!$field.length) {
+    return '';
+  }
+
+  return String($field.val() || '');
+}
+
+function setAddressSectionFieldValue($addressForm, sectionSelector, fieldsSelector, fieldName, value) {
+  if (typeof value === 'undefined' || value === null || String(value) === '') {
+    return;
+  }
+
+  const $section = getAddressSection($addressForm, sectionSelector, fieldsSelector);
+  if (!$section.length) {
+    return;
+  }
+
+  const $field = $section.find(`[name="${fieldName}"]`).first();
+  if (!$field.length) {
+    return;
+  }
+
+  $field.val(String(value));
+}
+
+function getUseSameAddressField($scope) {
+  return $scope.find(OPC_SELECTORS.opc.useSameAddress).first();
+}
+
+function getUseSameAddressState($scope) {
+  const $field = getUseSameAddressField($scope);
+
+  if (!$field.length) {
+    return false;
+  }
+
+  return $field.is(':checked');
+}
+
+function setUseSameAddressState($scope, useSameAddress) {
+  getUseSameAddressField($scope).prop('checked', useSameAddress);
+}
+
+function syncBillingSectionConstraints($addressForm, useSameAddress) {
+  const $billingSection = $addressForm.find(BILLING_SECTION_SELECTOR).first();
+
+  if (!$billingSection.length) {
+    return;
+  }
+
+  $billingSection.toggle(!useSameAddress);
+
+  $billingSection.find('input, select, textarea').each((_, field) => {
+    const $field = $(field);
+
+    if (useSameAddress) {
+      if (!$field.prop('disabled')) {
+        $field.attr(DISABLED_BY_SAME_ADDRESS_ATTRIBUTE, '1');
+        $field.prop('disabled', true);
+      }
+
+      return;
+    }
+
+    if ($field.attr(DISABLED_BY_SAME_ADDRESS_ATTRIBUTE) === '1') {
+      $field.prop('disabled', false);
+      $field.removeAttr(DISABLED_BY_SAME_ADDRESS_ATTRIBUTE);
+    }
+  });
+}
+
+function resetModalFields($modal) {
+  ADDRESS_FIELDS.forEach((fieldName) => {
+    if (fieldName === 'id_address') {
+      getModalField($modal, fieldName).val('');
+
+      return;
+    }
+
+    const $field = getModalField($modal, fieldName);
+    if (!$field.length) {
+      return;
+    }
+
+    if ($field.is('select')) {
+      $field.val('');
+
+      return;
+    }
+
+    $field.val('');
+  });
+}
+
+function clearValidationErrors($modal) {
+  $modal.find(`.${FIELD_ERROR_CLASS}`).remove();
+  $modal.find(`.${GLOBAL_ERROR_CLASS}`).remove();
+  $modal.find('.is-invalid').removeClass('is-invalid');
+}
+
+function isVisibleModalField(field) {
+  if (!(field instanceof HTMLElement)) {
+    return false;
+  }
+
+  const computedStyle = window.getComputedStyle(field);
+
+  return computedStyle.display !== 'none'
+    && computedStyle.visibility !== 'hidden'
+    && field.getClientRects().length > 0;
+}
+
+function isModalFieldValid(field) {
+  if (
+    !(field instanceof HTMLInputElement)
+    && !(field instanceof HTMLSelectElement)
+    && !(field instanceof HTMLTextAreaElement)
+  ) {
+    return true;
+  }
+
+  if (field.disabled || !isVisibleModalField(field)) {
+    return true;
+  }
+
+  return field.checkValidity();
+}
+
+function updateModalSaveState($modal) {
+  const $saveButtons = $modal.find(SAVE_SELECTOR);
+
+  if (!$saveButtons.length) {
+    return;
+  }
+
+  const modalElement = $modal.get(0);
+  const isOpen = modalElement instanceof HTMLElement && $modal.hasClass('show');
+  if (!isOpen) {
+    $saveButtons.prop('disabled', true);
+
+    return;
+  }
+
+  const isValid = $modal
+    .find('input, select, textarea')
+    .toArray()
+    .every((field) => isModalFieldValid(field));
+
+  $saveButtons.prop('disabled', !isValid);
+}
+
+function updateModalTitle($modal, type) {
+  const $title = $modal.find('.modal-header h2').first();
+
+  if (!$title.length) {
+    return;
+  }
+
+  const nextTitle = type === 'edit'
+    ? String($modal.attr('data-title-edit') || '')
+    : String($modal.attr('data-title-new') || '');
+
+  if (nextTitle !== '') {
+    $title.text(nextTitle);
+  }
+}
+
+function populateForm($modal, address) {
+  if (!address || typeof address !== 'object') {
+    return;
+  }
+
+  ADDRESS_FIELDS.forEach((fieldName) => {
+    const value = typeof address[fieldName] === 'undefined' ? '' : address[fieldName];
+    const $field = getModalField($modal, fieldName);
+
+    if (!$field.length) {
+      return;
+    }
+
+    $field.val(value);
+  });
+}
+
+function getAddressFromTrigger($trigger) {
+  const address = {};
+
+  ADDRESS_FIELDS.forEach((fieldName) => {
+    const attributeValue = $trigger.attr(`data-${fieldName}`);
+
+    if (typeof attributeValue !== 'undefined') {
+      address[fieldName] = attributeValue;
+    }
+  });
+
+  return address;
+}
+
+function getModalType($trigger) {
+  return String($trigger.attr('data-type') || 'create');
+}
+
+function readStateUiTargets($modal) {
+  return {
+    $wrapper: $modal.find('.state-field-wrapper, #state-field-wrapper').first(),
+    $select: $modal.find(STATE_SELECTOR).first(),
+    $row: $modal.find('.address-country-row, #address-country-row').first(),
+  };
+}
+
+function updateStateFieldUi($modal, response, selectedStateId) {
+  const {$wrapper, $select, $row} = readStateUiTargets($modal);
+
+  if (!$wrapper.length || !$select.length) {
+    return;
+  }
+
+  const states = response && Array.isArray(response.states) ? response.states : [];
+  const hasStates = Boolean(response && response.hasStates) || states.length > 0;
+
+  if (!hasStates) {
+    $wrapper.hide();
+    $select.prop('required', false).val('');
+    if ($row.length) {
+      $row.removeClass('form-fields-row--3').addClass('form-fields-row--2');
+    }
+
+    return;
+  }
+
+  const placeholder = String($select.attr('data-select-placeholder') || '');
+  $select.empty();
+  $select.append($('<option>', {value: '', text: placeholder}));
+
+  states.forEach((state) => {
+    const stateId = String(state.id_state || '');
+    $select.append($('<option>', {
+      value: stateId,
+      text: String(state.name || ''),
+      selected: selectedStateId !== '' && stateId === selectedStateId,
+    }));
+  });
+
+  $wrapper.show();
+  $select.prop('required', true);
+  if ($row.length) {
+    $row.removeClass('form-fields-row--2').addClass('form-fields-row--3');
+  }
+}
+
+function refreshStates($modal, countryId, selectedStateId) {
+  const statesUrl = getConfiguredOpcUrl(URL_KEYS.states);
+
+  if (!statesUrl || countryId === '') {
+    updateStateFieldUi($modal, {hasStates: false, states: []}, '');
+
+    return $.Deferred().resolve().promise();
+  }
+
+  return $.get(statesUrl, {id_country: countryId}).done((response) => {
+    updateStateFieldUi($modal, response || {}, selectedStateId);
+    updateModalSaveState($modal);
+  }).fail((jqXHR) => {
+    updateStateFieldUi($modal, {hasStates: false, states: []}, '');
+    updateModalSaveState($modal);
+    prestashop.emit('handleError', {
+      eventType: 'opcAddressStates',
+      resp: jqXHR.responseJSON || {errors: {'': ['Unable to load states.']}},
+    });
+  });
+}
+
+function showDeleteConfirmation() {
+  const deferred = $.Deferred();
+  const $modal = $(`#${DELETE_CONFIRM_MODAL_ID}`);
+  let confirmed = false;
+
+  if (!$modal.length) {
+    deferred.resolve(false);
+
+    return deferred.promise();
+  }
+
+  const handleConfirm = () => {
+    confirmed = true;
+    hideModal($modal);
+  };
+
+  const handleHidden = () => {
+    $modal.off('.opcDeleteConfirm');
+    deferred.resolve(confirmed);
+  };
+
+  $modal.on('click.opcDeleteConfirm', '.js-opc-delete-address-confirm', handleConfirm);
+  $modal.on('hidden.bs.modal.opcDeleteConfirm', handleHidden);
+  showModal($modal);
+
+  return deferred.promise();
+}
+
+function appendFieldError($field, message) {
+  if (!$field.length || !message) {
+    return;
+  }
+
+  $field.addClass('is-invalid');
+
+  const $target = $field.closest('.form-group').length ? $field.closest('.form-group') : $field.parent();
+  $target.append($('<div>', {
+    class: `invalid-feedback d-block ${FIELD_ERROR_CLASS}`,
+    text: message,
+  }));
+}
+
+function renderValidationErrors($modal, errors) {
+  clearValidationErrors($modal);
+
+  if (!errors || typeof errors !== 'object') {
+    return;
+  }
+
+  Object.entries(errors).forEach(([fieldName, fieldErrors]) => {
+    const messages = Array.isArray(fieldErrors) ? fieldErrors.filter(Boolean) : [];
+    if (messages.length === 0) {
+      return;
+    }
+
+    if (fieldName === '') {
+      $modal.find('.modal-body').first().prepend($('<div>', {
+        class: `alert alert-danger ${GLOBAL_ERROR_CLASS}`,
+        text: messages.join(' '),
+      }));
+
+      return;
+    }
+
+    appendFieldError(getModalField($modal, fieldName), messages[0]);
+  });
+}
+
+function getAddressListSelectorForRadioName(radioName) {
+  if (radioName === 'id_address_delivery') {
+    return OPC_SELECTORS.opc.deliveryList;
+  }
+
+  if (radioName === 'id_address_invoice') {
+    return OPC_SELECTORS.opc.billingList;
+  }
+
+  return '';
+}
+
+function getAddressModalForRadioName(radioName) {
+  if (radioName === 'id_address_delivery') {
+    return $('#modal-delivery');
+  }
+
+  if (radioName === 'id_address_invoice') {
+    return $('#modal-invoice');
+  }
+
+  return $();
+}
+
+function clearRememberedSelection($modal) {
+  $modal.removeAttr(RESTORE_SELECTION_ID_ATTRIBUTE);
+  $modal.removeAttr(RESTORE_SELECTION_RADIO_NAME_ATTRIBUTE);
+  $modal.removeAttr(SKIP_RESTORE_SELECTION_ATTRIBUTE);
+}
+
+function rememberSelectedSavedAddressBeforeCreate(radioName) {
+  const listSelector = getAddressListSelectorForRadioName(radioName);
+  const $modal = getAddressModalForRadioName(radioName);
+
+  if (!listSelector || !$modal.length) {
+    return;
+  }
+
+  const previousSelection = getSelectedSavedAddress(listSelector, radioName);
+
+  clearRememberedSelection($modal);
+
+  if (!previousSelection.idAddress) {
+    return;
+  }
+
+  $modal.attr(RESTORE_SELECTION_ID_ATTRIBUTE, previousSelection.idAddress);
+  $modal.attr(RESTORE_SELECTION_RADIO_NAME_ATTRIBUTE, radioName);
+}
+
+function restoreRememberedSelection($modal) {
+  if ($modal.attr(SKIP_RESTORE_SELECTION_ATTRIBUTE) === '1') {
+    clearRememberedSelection($modal);
+
+    return;
+  }
+
+  const radioName = String($modal.attr(RESTORE_SELECTION_RADIO_NAME_ATTRIBUTE) || '');
+  const addressId = String($modal.attr(RESTORE_SELECTION_ID_ATTRIBUTE) || '');
+  const listSelector = getAddressListSelectorForRadioName(radioName);
+
+  clearRememberedSelection($modal);
+
+  if (!radioName || !addressId || !listSelector) {
+    return;
+  }
+
+  const $radio = $(listSelector)
+    .find(`${OPC_SELECTORS.opc.addressRadio}[name="${radioName}"][value="${addressId}"]`)
+    .first();
+
+  if (!$radio.length) {
+    return;
+  }
+
+  if ($radio.is(':checked')) {
+    syncAddressItemStyles($radio.closest(OPC_SELECTORS.opc.addressItem).parent());
+
+    return;
+  }
+
+  $radio.prop('checked', true);
+  syncAddressItemStyles($radio.closest(OPC_SELECTORS.opc.addressItem).parent());
+}
+
+function showSuccessMessage(message) {
+  const normalizedMessage = String(message || '').trim();
+  if (normalizedMessage === '') {
+    return;
+  }
+
+  if (window.Theme && window.Theme.components && typeof window.Theme.components.useToast === 'function') {
+    const toast = window.Theme.components.useToast(normalizedMessage, {type: 'success'});
+
+    if (toast && typeof toast.show === 'function') {
+      toast.show();
+    }
+
+    return;
+  }
+
+  $('body').append($('<div>', {
+    class: 'alert alert-success',
+    text: normalizedMessage,
+  }));
+}
+
+function serializeModalFields($modal) {
+  const serializedFields = [];
+
+  $modal.find('input, select, textarea').each((_, field) => {
+    const $field = $(field);
+    const name = String($field.attr('name') || '');
+
+    if (name === '' || $field.prop('disabled')) {
+      return;
+    }
+
+    if (($field.is(':checkbox') || $field.is(':radio')) && !$field.is(':checked')) {
+      return;
+    }
+
+    serializedFields.push({
+      name,
+      value: String($field.val() || ''),
+    });
+  });
+
+  serializedFields.push({
+    name: 'use_same_address',
+    value: getUseSameAddressState($(OPC_ADDRESSES_SECTION_SELECTOR).first()) ? '1' : '0',
+  });
+
+  return $.param(serializedFields);
+}
+
+function showModal($modal) {
+  if (!$modal.length) {
+    return;
+  }
+
+  if (window.bootstrap && typeof window.bootstrap.Modal === 'function') {
+    window.bootstrap.Modal.getOrCreateInstance($modal.get(0)).show();
+
+    return;
+  }
+
+  if (typeof $modal.modal === 'function') {
+    $modal.modal('show');
+  }
+}
+
+function hideModal($modal) {
+  if (!$modal.length) {
+    return;
+  }
+
+  if (window.bootstrap && typeof window.bootstrap.Modal === 'function') {
+    const instance = window.bootstrap.Modal.getInstance($modal.get(0));
+
+    if (instance) {
+      instance.hide();
+
+      return;
+    }
+  }
+
+  if (typeof $modal.modal === 'function') {
+    $modal.modal('hide');
+  }
+}
+
+function refreshAddressesSection(options = {}) {
+  const addressFormUrl = getConfiguredOpcUrl(URL_KEYS.addressForm);
+  const $addressForm = $(OPC_ADDRESSES_SECTION_SELECTOR).first();
+  const resetInlineAddressState = Boolean(options.resetInlineAddressState);
+
+  if (!addressFormUrl || !$addressForm.length) {
+    return $.Deferred().resolve().promise();
+  }
+
+  const payload = {
+    use_same_address: getUseSameAddressState($addressForm) ? '1' : '0',
+  };
+
+  if (!resetInlineAddressState) {
+    payload.id_address_delivery = getAddressSectionFieldValue($addressForm, DELIVERY_SECTION_SELECTOR, DELIVERY_FIELDS_SELECTOR, 'id_address_delivery');
+    payload.id_address_invoice = getAddressSectionFieldValue($addressForm, BILLING_SECTION_SELECTOR, BILLING_FIELDS_SELECTOR, 'id_address_invoice');
+    payload.id_country = getAddressSectionFieldValue($addressForm, DELIVERY_SECTION_SELECTOR, DELIVERY_FIELDS_SELECTOR, 'id_country');
+    payload.invoice_id_country = getAddressSectionFieldValue($addressForm, BILLING_SECTION_SELECTOR, BILLING_FIELDS_SELECTOR, 'invoice_id_country');
+  }
+
+  const useSameAddress = payload.use_same_address !== '0';
+  const preservedFields = preserveAddressesSectionFields($addressForm);
+
+  return $.post(addressFormUrl, payload).done((response) => {
+    if (!response || typeof response.addresses_section !== 'string') {
+      return;
+    }
+
+    $addressForm.html(response.addresses_section);
+    restoreAddressesSectionFields($addressForm, preservedFields);
+    setUseSameAddressState($addressForm, useSameAddress);
+    syncBillingSectionConstraints($addressForm, useSameAddress);
+    if (!resetInlineAddressState) {
+      setAddressSectionFieldValue($addressForm, DELIVERY_SECTION_SELECTOR, DELIVERY_FIELDS_SELECTOR, 'id_country', payload.id_country);
+      setAddressSectionFieldValue($addressForm, BILLING_SECTION_SELECTOR, BILLING_FIELDS_SELECTOR, 'invoice_id_country', payload.invoice_id_country);
+    }
+
+    syncAllSavedAddressItemStyles();
+    prestashop.emit(OPC_EVENTS.updatedOpcAddressForm, {target: $addressForm, resp: response});
+    prestashop.emit(OPC_EVENTS.opcDeliveryAddressUpdated, {resp: response});
+    prestashop.emit(OPC_EVENTS.opcBillingAddressUpdated, {resp: response});
+  });
+}
+
+function syncAddressItemStyles($scope) {
+  if (!$scope.length) {
+    return;
+  }
+
+  $scope.find(OPC_SELECTORS.opc.addressItem).each((_, item) => {
+    const $item = $(item);
+    const isSelected = $item.find(OPC_SELECTORS.opc.addressRadio).first().is(':checked');
+
+    $item.toggleClass('border-primary selected z-1', isSelected);
+    $item.find(OPC_SELECTORS.opc.addressLabel).first().toggleClass('fw-semibold', isSelected);
+  });
+}
+
+function syncAllSavedAddressItemStyles() {
+  syncAddressItemStyles($(OPC_SELECTORS.opc.deliveryList));
+  syncAddressItemStyles($(OPC_SELECTORS.opc.billingList));
+}
+
+function renderAddressListsLoadingState() {
+  [
+    [OPC_SELECTORS.opc.deliveryList, '#opc-delivery-address-loader'],
+    [OPC_SELECTORS.opc.billingList, '#opc-billing-address-loader'],
+  ].forEach(([listSelector, templateSelector]) => {
+    const $list = $(listSelector);
+    const templateHtml = $(templateSelector).html();
+
+    if ($list.length && templateHtml) {
+      $list.html(templateHtml);
+    }
+  });
+}
+
+function applyAddressListsResponse(response, options = {}) {
+  const previousDeliverySelection = getSelectedSavedAddress(OPC_SELECTORS.opc.deliveryList, 'id_address_delivery');
+  const previousBillingSelection = getSelectedSavedAddress(OPC_SELECTORS.opc.billingList, 'id_address_invoice');
+  const addressCount = parseInt(response.address_count, 10) || 0;
+  const $deliveryList = $(OPC_SELECTORS.opc.deliveryList);
+  const $deliveryFields = $(DELIVERY_FIELDS_SELECTOR);
+  const $billingList = $(OPC_SELECTORS.opc.billingList);
+  const $billingFields = $(BILLING_FIELDS_SELECTOR);
+
+  if ($deliveryList.length && typeof response.delivery_html === 'string') {
+    $deliveryList.html(response.delivery_html);
+  }
+
+  if ($billingList.length && typeof response.billing_html === 'string') {
+    $billingList.html(response.billing_html);
+  }
+
+  $deliveryList.toggleClass('d-none', addressCount <= 0);
+  $deliveryFields.toggleClass('d-none', addressCount > 0);
+
+  $billingList.toggleClass('d-none', addressCount <= 1);
+  $billingFields.toggleClass('d-none', addressCount > 1);
+
+  syncAllSavedAddressItemStyles();
+
+  emitSavedAddressSelectionIfNeeded(
+    OPC_EVENTS.opcDeliveryAddressSelected,
+    previousDeliverySelection,
+    getSelectedSavedAddress(OPC_SELECTORS.opc.deliveryList, 'id_address_delivery'),
+    Boolean(options.refreshDeliverySelection)
+  );
+  emitSavedAddressSelectionIfNeeded(
+    OPC_EVENTS.opcBillingAddressSelected,
+    previousBillingSelection,
+    getSelectedSavedAddress(OPC_SELECTORS.opc.billingList, 'id_address_invoice'),
+    Boolean(options.refreshBillingSelection)
+  );
+}
+
+function refreshAddressLists(options = {}) {
+  const addressesListUrl = getConfiguredOpcUrl(URL_KEYS.addressesList);
+
+  if (!addressesListUrl) {
+    return refreshAddressesSection(options);
+  }
+
+  renderAddressListsLoadingState();
+
+  return $.post(addressesListUrl)
+    .then((response) => {
+      if (!response || response.success === false || typeof response.address_count === 'undefined') {
+        return refreshAddressesSection(options);
+      }
+
+      const addressCount = parseInt(response.address_count, 10) || 0;
+
+      if (addressCount <= 0) {
+        return refreshAddressesSection(options);
+      }
+
+      applyAddressListsResponse(response, options);
+
+      return response;
+    })
+    .fail((jqXHR) => {
+      prestashop.emit('handleError', {eventType: 'opcAddressesList', resp: jqXHR.responseJSON || {}});
+
+      return refreshAddressesSection(options);
+    });
+}
+
+function getSelectedSavedAddress(listSelector, radioName) {
+  const $radio = $(listSelector).find(`${OPC_SELECTORS.opc.addressRadio}[name="${radioName}"]:checked`).first();
+  const addressId = String($radio.val() || '');
+
+  if (!$radio.length || addressId === '' || addressId === 'new_address') {
+    return {
+      idAddress: '',
+      target: null,
+    };
+  }
+
+  const $item = $radio.closest(OPC_SELECTORS.opc.addressItem);
+
+  return {
+    idAddress: addressId,
+    target: $item.length ? $item.get(0) : $radio.get(0),
+  };
+}
+
+function emitSavedAddressSelectionIfNeeded(eventName, previousSelection, currentSelection, forceRefresh = false) {
+  if (!currentSelection.idAddress) {
+    return;
+  }
+
+  if (!forceRefresh && previousSelection.idAddress === currentSelection.idAddress) {
+    return;
+  }
+
+  prestashop.emit(eventName, currentSelection);
+}
+
+$(document).on('show.bs.modal', MODAL_SELECTOR, (event) => {
+  const $modal = $(event.currentTarget);
+  const $trigger = $(event.relatedTarget);
+  const modalType = getModalType($trigger);
+  let triggerAddress = null;
+
+  $modal.removeAttr(SKIP_RESTORE_SELECTION_ATTRIBUTE);
+  if (modalType !== 'create') {
+    $modal.removeAttr(RESTORE_SELECTION_ID_ATTRIBUTE);
+    $modal.removeAttr(RESTORE_SELECTION_RADIO_NAME_ATTRIBUTE);
+  }
+  updateModalTitle($modal, modalType);
+  clearValidationErrors($modal);
+  resetModalFields($modal);
+
+  if (modalType === 'edit') {
+    triggerAddress = getAddressFromTrigger($trigger);
+    populateForm($modal, triggerAddress);
+  }
+
+  const selectedCountryId = modalType === 'edit' && triggerAddress
+    ? String(triggerAddress.id_country || '')
+    : String(getModalField($modal, 'id_country').val() || '');
+  const selectedStateId = modalType === 'edit' && triggerAddress
+    ? String(triggerAddress.id_state || '')
+    : String(getModalField($modal, 'id_state').val() || '');
+
+  setModalFieldsDisabled($modal, false);
+  refreshStates($modal, selectedCountryId, selectedStateId);
+});
+
+$(document).on('shown.bs.modal', MODAL_SELECTOR, (event) => {
+  const $modal = $(event.currentTarget);
+  setModalFieldsDisabled($modal, false);
+  updateModalSaveState($modal);
+});
+
+$(document).on('hidden.bs.modal', MODAL_SELECTOR, (event) => {
+  const $modal = $(event.currentTarget);
+  restoreRememberedSelection($modal);
+  clearValidationErrors($modal);
+  setModalFieldsDisabled($modal, true);
+  updateModalSaveState($modal);
+});
+
+$(document).on('change', MODAL_COUNTRY_SELECTOR, (event) => {
+  const $modal = $(event.currentTarget).closest(MODAL_SELECTOR);
+  const countryId = String($(event.currentTarget).val() || '');
+
+  refreshStates($modal, countryId, '');
+});
+
+$(document).on('input change', MODAL_FIELD_SELECTOR, (event) => {
+  updateModalSaveState($(event.currentTarget).closest(MODAL_SELECTOR));
+});
+
+$(document).on('click', OPC_SELECTORS.opc.addressItem, (event) => {
+  const $target = $(event.target);
+  const $item = $target.closest(OPC_SELECTORS.opc.addressItem);
+
+  if (!$item.length || $target.closest('.opc-address-card__actions').length) {
+    return;
+  }
+
+  const $radio = $item.find(OPC_SELECTORS.opc.addressRadio).first();
+  if (!$radio.length) {
+    return;
+  }
+
+  if (!$radio.is(':checked')) {
+    if (String($radio.val() || '') === 'new_address') {
+      rememberSelectedSavedAddressBeforeCreate(String($radio.attr('name') || ''));
+    }
+
+    $radio.prop('checked', true).trigger('change');
+
+    return;
+  }
+
+  syncAddressItemStyles($item.parent());
+});
+
+$(document).on('change', OPC_SELECTORS.opc.addressRadio, (event) => {
+  const $radio = $(event.currentTarget);
+  const $item = $radio.closest(OPC_SELECTORS.opc.addressItem);
+  const $scope = $item.parent();
+  const selectedAddressId = String($radio.val() || '');
+  const radioName = String($radio.attr('name') || '');
+
+  syncAddressItemStyles($scope);
+
+  if (selectedAddressId === '' || selectedAddressId === 'new_address') {
+    return;
+  }
+
+  if (radioName === 'id_address_delivery') {
+    prestashop.emit(OPC_EVENTS.opcDeliveryAddressSelected, {
+      idAddress: selectedAddressId,
+      target: $item.get(0),
+    });
+
+    return;
+  }
+
+  if (radioName === 'id_address_invoice') {
+    prestashop.emit(OPC_EVENTS.opcBillingAddressSelected, {
+      idAddress: selectedAddressId,
+      target: $item.get(0),
+    });
+  }
+});
+
+$(document).on('click', MODAL_SAVE_SELECTOR, (event) => {
+  event.preventDefault();
+
+  const saveAddressUrl = getConfiguredOpcUrl(URL_KEYS.saveAddress);
+  const $button = $(event.currentTarget);
+  const $modal = $button.closest(MODAL_SELECTOR);
+
+  if (!saveAddressUrl || !$modal.length) {
+    prestashop.emit('handleError', {eventType: 'opcSaveAddress', resp: {errors: {'': ['Missing OPC save address URL.']}}});
+
+    return;
+  }
+
+  setModalFieldsDisabled($modal, false);
+  const initialText = String($button.attr('data-text') || $button.text());
+  const loadingText = String($button.attr('data-loading-text') || initialText);
+  const payload = serializeModalFields($modal);
+  const payloadParams = new URLSearchParams(payload);
+  const addressType = String(payloadParams.get('address_type') || ($modal.is('#modal-invoice') ? 'invoice' : 'delivery'));
+
+  $button.prop('disabled', true).text(loadingText);
+
+  $.post(saveAddressUrl, payload)
+    .done((response) => {
+      if (!response || response.success === false) {
+        renderValidationErrors($modal, response && response.errors ? response.errors : {});
+        prestashop.emit('handleError', {eventType: 'opcSaveAddress', resp: response || {}});
+
+        return;
+      }
+
+      clearValidationErrors($modal);
+      $modal.attr(SKIP_RESTORE_SELECTION_ATTRIBUTE, '1');
+      hideModal($modal);
+      refreshAddressLists({
+        refreshDeliverySelection: addressType === 'delivery',
+        refreshBillingSelection: addressType === 'invoice',
+      });
+      showSuccessMessage(response.message || '');
+    })
+    .fail((jqXHR) => {
+      prestashop.emit('handleError', {eventType: 'opcSaveAddress', resp: jqXHR.responseJSON || {}});
+    })
+    .always(() => {
+      $button.prop('disabled', false).text(initialText);
+    });
+});
+
+$(document).on('click', '.js-delete-address', (event) => {
+  event.preventDefault();
+
+  const deleteAddressUrl = getConfiguredOpcUrl(URL_KEYS.deleteAddress);
+  const $button = $(event.currentTarget);
+
+  if (!deleteAddressUrl || !$button.length) {
+    prestashop.emit('handleError', {eventType: 'opcDeleteAddress', resp: {errors: {'': ['Missing OPC delete address URL.']}}});
+
+    return;
+  }
+
+  showDeleteConfirmation().then((confirmed) => {
+    if (!confirmed) {
+      return;
+    }
+
+    $button.prop('disabled', true);
+
+    $.post(deleteAddressUrl, {
+      id_address: String($button.attr('data-id-address') || ''),
+    })
+      .done((response) => {
+        if (!response || response.success === false) {
+          prestashop.emit('handleError', {eventType: 'opcDeleteAddress', resp: response || {}});
+          $button.prop('disabled', false);
+
+          return;
+        }
+
+        refreshAddressLists({
+          resetInlineAddressState: true,
+        });
+        showSuccessMessage(response.message || '');
+      })
+      .fail((jqXHR) => {
+        prestashop.emit('handleError', {eventType: 'opcDeleteAddress', resp: jqXHR.responseJSON || {}});
+        $button.prop('disabled', false);
+      });
+  });
+});
+
+$(function () {
+  disableClosedModalFields();
+  $(MODAL_SELECTOR).each((_, modal) => updateModalSaveState($(modal)));
+  syncAllSavedAddressItemStyles();
+  retriggerCheckoutValidation();
+});
+
+prestashop.on(OPC_EVENTS.updatedOpcAddressForm, () => {
+  disableClosedModalFields();
+  $(MODAL_SELECTOR).each((_, modal) => updateModalSaveState($(modal)));
+  retriggerCheckoutValidation();
+});
+}());
diff --git a/views/js/opc-address.js b/views/js/opc-address.js
index 40db87f..5209da9 100644
--- a/views/js/opc-address.js
+++ b/views/js/opc-address.js
@@ -1,3 +1,7 @@
+import OPC_EVENTS from './events';
+import OPC_SELECTORS from './selectors';
+import {getConfiguredOpcUrl} from './runtime/opc-runtime';
+
 /**
  * Copyright since 2007 PrestaShop SA and Contributors
  * PrestaShop is an International Registered Trademark & Property of PrestaShop SA
@@ -27,7 +31,12 @@ const $ = window.$ || window.jQuery;
 const prestashop = window.prestashop || {};
 
 const MODULE_ADDRESS_FORM_URL_KEY = 'addressForm';
-const BILLING_SECTION_SELECTOR = '#opc-billing-section';
+const OPC_ADDRESSES_SECTION_SELECTOR = OPC_SELECTORS.opc.addressesSection;
+const BILLING_SECTION_SELECTOR = OPC_SELECTORS.opc.billingSection;
+const DELIVERY_SECTION_SELECTOR = OPC_SELECTORS.opc.deliverySection;
+const DELIVERY_FIELDS_SELECTOR = OPC_SELECTORS.opc.deliveryFields;
+const BILLING_FIELDS_SELECTOR = OPC_SELECTORS.opc.billingFields;
+const ADDRESS_MODAL_SELECTOR = OPC_SELECTORS.modals.address;
 const SAME_ADDRESS_SELECTOR = '[name="use_same_address"]';
 const DISABLED_BY_SAME_ADDRESS_ATTRIBUTE = 'data-opc-disabled-by-same-address';
 
@@ -54,6 +63,10 @@ function isClientPreservableField(name, $field) {
     return false;
   }
 
+  if ($field.closest(ADDRESS_MODAL_SELECTOR).length > 0) {
+    return false;
+  }
+
   return !NON_PRESERVABLE_FIELD_TYPES.has(getFieldType($field));
 }
 
@@ -153,24 +166,6 @@ function restoreAddressFormFields(formFieldsSelector, preservedFields) {
   });
 }
 
-function getOpcRuntimeConfiguration() {
-  if (!window || typeof window.ps_onepagecheckout !== 'object' || !window.ps_onepagecheckout) {
-    return null;
-  }
-
-  return window.ps_onepagecheckout;
-}
-
-function getConfiguredOpcUrl(urlKey) {
-  const runtimeConfiguration = getOpcRuntimeConfiguration();
-
-  if (runtimeConfiguration && runtimeConfiguration.urls && runtimeConfiguration.urls[urlKey]) {
-    return String(runtimeConfiguration.urls[urlKey]);
-  }
-
-  return '';
-}
-
 function syncBillingSectionConstraints(addressContainer, useSameAddress) {
   const billingSection = addressContainer.find(BILLING_SECTION_SELECTOR);
 
@@ -200,7 +195,139 @@ function syncBillingSectionConstraints(addressContainer, useSameAddress) {
 }
 
 function getUseSameAddressState(addressContainer) {
-  return addressContainer.find(SAME_ADDRESS_SELECTOR).is(':checked');
+  return addressContainer.find(SAME_ADDRESS_SELECTOR).first().is(':checked');
+}
+
+function setUseSameAddressState(addressContainer, useSameAddress) {
+  addressContainer.find(SAME_ADDRESS_SELECTOR).first().prop('checked', useSameAddress);
+}
+
+function getAddressSection(addressContainer, sectionSelector, fieldsSelector) {
+  const $fields = addressContainer.find(fieldsSelector).first();
+  if ($fields.length) {
+    return $fields;
+  }
+
+  return addressContainer.find(sectionSelector).first();
+}
+
+function getAddressSectionFieldValue(addressContainer, sectionSelector, fieldsSelector, fieldName) {
+  const $section = getAddressSection(addressContainer, sectionSelector, fieldsSelector);
+  if (!$section.length) {
+    return '';
+  }
+
+  const $field = $section.find(`[name="${fieldName}"]`).first();
+  if (!$field.length) {
+    return '';
+  }
+
+  return String($field.val() || '');
+}
+
+function setAddressSectionFieldValue(addressContainer, sectionSelector, fieldsSelector, fieldName, value) {
+  if (typeof value === 'undefined' || value === null || String(value) === '') {
+    return;
+  }
+
+  const $section = getAddressSection(addressContainer, sectionSelector, fieldsSelector);
+  if (!$section.length) {
+    return;
+  }
+
+  const $field = $section.find(`[name="${fieldName}"]`).first();
+  if (!$field.length) {
+    return;
+  }
+
+  $field.val(String(value));
+}
+
+function hasMeaningfulFieldValue($field) {
+  const type = getFieldType($field);
+
+  if (type === 'checkbox' || type === 'radio') {
+    return $field.is(':checked');
+  }
+
+  return String($field.val() || '').trim() !== '';
+}
+
+function hasSeparateBillingDraft(addressContainer) {
+  if (getAddressSectionFieldValue(addressContainer, BILLING_SECTION_SELECTOR, BILLING_FIELDS_SELECTOR, 'id_address_invoice') !== '') {
+    return true;
+  }
+
+  const billingSection = getAddressSection(addressContainer, BILLING_SECTION_SELECTOR, BILLING_FIELDS_SELECTOR);
+
+  if (!billingSection.length) {
+    return false;
+  }
+
+  let hasDraft = false;
+
+  billingSection.find('input, select, textarea').each(function () {
+    const $field = $(this);
+    const name = String($field.prop('name') || '');
+
+    if (!isClientPreservableField(name, $field)) {
+      return;
+    }
+
+    if (!hasMeaningfulFieldValue($field)) {
+      return;
+    }
+
+    hasDraft = true;
+
+    return false;
+  });
+
+  return hasDraft;
+}
+
+function seedBillingFromDelivery(addressContainer) {
+  const deliveryCountryValue = getAddressSectionFieldValue(
+    addressContainer,
+    DELIVERY_SECTION_SELECTOR,
+    DELIVERY_FIELDS_SELECTOR,
+    'id_country'
+  );
+  const deliveryStateValue = getAddressSectionFieldValue(
+    addressContainer,
+    DELIVERY_SECTION_SELECTOR,
+    DELIVERY_FIELDS_SELECTOR,
+    'id_state'
+  );
+  const billingCountryField = getAddressSection(
+    addressContainer,
+    BILLING_SECTION_SELECTOR,
+    BILLING_FIELDS_SELECTOR
+  ).find('[name="invoice_id_country"]').first();
+  const previousBillingCountryValue = billingCountryField.length
+    ? String(billingCountryField.val() || '')
+    : '';
+
+  setAddressSectionFieldValue(
+    addressContainer,
+    BILLING_SECTION_SELECTOR,
+    BILLING_FIELDS_SELECTOR,
+    'invoice_id_country',
+    deliveryCountryValue
+  );
+
+  if (billingCountryField.length && deliveryCountryValue !== '' && previousBillingCountryValue !== deliveryCountryValue) {
+    billingCountryField.val(deliveryCountryValue).trigger('change');
+    return;
+  }
+
+  setAddressSectionFieldValue(
+    addressContainer,
+    BILLING_SECTION_SELECTOR,
+    BILLING_FIELDS_SELECTOR,
+    'invoice_id_state',
+    deliveryStateValue
+  );
 }
 
 function bindBillingToggleListener(selectors) {
@@ -211,7 +338,13 @@ function bindBillingToggleListener(selectors) {
       return;
     }
 
-    syncBillingSectionConstraints(addressContainer, getUseSameAddressState(addressContainer));
+    const useSameAddress = getUseSameAddressState(addressContainer);
+
+    syncBillingSectionConstraints(addressContainer, useSameAddress);
+
+    if (!useSameAddress && !hasSeparateBillingDraft(addressContainer)) {
+      seedBillingFromDelivery(addressContainer);
+    }
   });
 }
 
@@ -230,65 +363,90 @@ function initializeBillingSectionConstraints(selectors) {
  *
  * @param selectors
  */
-function handleOpcCountryChange(selectors) {
-  $('body').on('change', selectors.country, (event) => {
-    const target = $(event.target);
-    const addressContainer = target.closest(selectors.address);
+function refreshOpcAddressFormForCountryChange(target, selectors) {
+  if (!target.length) {
+    return;
+  }
 
-    if (!addressContainer.length) {
-      return;
-    }
+  if (target.closest(ADDRESS_MODAL_SELECTOR).length > 0) {
+    return;
+  }
+
+  if ($(ADDRESS_MODAL_SELECTOR).filter('.show').length > 0) {
+    return;
+  }
+
+  const addressContainer = target.closest(selectors.address);
+
+  if (!addressContainer.length) {
+    return;
+  }
+
+  // Send both country values so backend rebuilds delivery and billing sections consistently.
+  const targetName = String(target.attr('name') || '');
+  const deliveryCountryValue = targetName === 'id_country'
+    ? String(target.val() || '')
+    : getAddressSectionFieldValue(addressContainer, DELIVERY_SECTION_SELECTOR, DELIVERY_FIELDS_SELECTOR, 'id_country');
+  const invoiceCountryValue = targetName === 'invoice_id_country'
+    ? String(target.val() || '')
+    : getAddressSectionFieldValue(addressContainer, BILLING_SECTION_SELECTOR, BILLING_FIELDS_SELECTOR, 'invoice_id_country');
+  const requestData = {
+    id_address_delivery: getAddressSectionFieldValue(addressContainer, DELIVERY_SECTION_SELECTOR, DELIVERY_FIELDS_SELECTOR, 'id_address_delivery'),
+    id_address_invoice: getAddressSectionFieldValue(addressContainer, BILLING_SECTION_SELECTOR, BILLING_FIELDS_SELECTOR, 'id_address_invoice'),
+    id_country: deliveryCountryValue,
+    invoice_id_country: invoiceCountryValue,
+    use_same_address: getUseSameAddressState(addressContainer) ? '1' : '0',
+  };
+  const formFieldsSelector = `${selectors.address} input, ${selectors.address} select, ${selectors.address} textarea`;
 
-    // Send both country values so backend rebuilds delivery and billing sections consistently.
-    const requestData = {
-      id_country: addressContainer.find('[name="id_country"]').val(),
-      invoice_id_country: addressContainer.find('[name="invoice_id_country"]').val(),
-      use_same_address: addressContainer.find('[name="use_same_address"]').is(':checked') ? '1' : '0',
-    };
-    const formFieldsSelector = `${selectors.address} input, ${selectors.address} select, ${selectors.address} textarea`;
-
-    const addressFormUrl = getConfiguredOpcUrl(MODULE_ADDRESS_FORM_URL_KEY);
-    if (addressFormUrl === '') {
-      prestashop.emit('handleError', {
-        eventType: 'updateOpcAddressForm',
-        resp: {errors: {'': ['Missing OPC address form URL.']}},
-      });
+  const addressFormUrl = getConfiguredOpcUrl(MODULE_ADDRESS_FORM_URL_KEY);
+  if (addressFormUrl === '') {
+    prestashop.emit('handleError', {
+      eventType: 'updateOpcAddressForm',
+      resp: {errors: {'': ['Missing OPC address form URL.']}},
+    });
+
+    return;
+  }
+
+  $.post(
+    addressFormUrl,
+    requestData,
+  ).then((resp) => {
+    if (!resp || typeof resp.addresses_section !== 'string') {
+      prestashop.emit('handleError', {eventType: 'updateOpcAddressForm', resp});
 
       return;
     }
 
-    $.post(
-      addressFormUrl,
-      requestData,
-    ).then((resp) => {
-      if (!resp || typeof resp.address_form !== 'string') {
-        prestashop.emit('handleError', {eventType: 'updateOpcAddressForm', resp});
+    const preservedFields = preserveAddressFormFields(formFieldsSelector);
 
-        return;
-      }
+    addressContainer.html(resp.addresses_section);
 
-      const preservedFields = preserveAddressFormFields(formFieldsSelector);
+    restoreAddressFormFields(formFieldsSelector, preservedFields);
 
-      addressContainer.html(resp.address_form);
+    // Backend template resets billing toggle; re-apply user choice.
+    const useSameAddress = requestData.use_same_address !== '0';
+    setUseSameAddressState(addressContainer, useSameAddress);
+    syncBillingSectionConstraints(addressContainer, useSameAddress);
 
-      restoreAddressFormFields(formFieldsSelector, preservedFields);
-
-      // Backend template resets billing toggle; re-apply user choice.
-      const useSameAddress = requestData.use_same_address !== '0';
-      addressContainer.find('[name="use_same_address"]').prop('checked', useSameAddress);
-      syncBillingSectionConstraints(addressContainer, useSameAddress);
+    prestashop.emit(OPC_EVENTS.updatedOpcAddressForm, {target: addressContainer, resp});
+    prestashop.emit(OPC_EVENTS.opcDeliveryAddressUpdated, {target: addressContainer, resp});
+    prestashop.emit(OPC_EVENTS.opcBillingAddressUpdated, {target: addressContainer, resp});
+  }).fail((resp) => {
+    prestashop.emit('handleError', {eventType: 'updateOpcAddressForm', resp});
+  });
+}
 
-      prestashop.emit('updatedOpcAddressForm', {target: $(selectors.address), resp});
-    }).fail((resp) => {
-      prestashop.emit('handleError', {eventType: 'updateOpcAddressForm', resp});
-    });
+function handleOpcCountryChange(selectors) {
+  $('body').on('change', `${OPC_SELECTORS.opc.deliveryFields} select[name="id_country"], ${OPC_SELECTORS.opc.billingFields} select[name="invoice_id_country"]`, (event) => {
+    refreshOpcAddressFormForCountryChange($(event.target), selectors);
   });
 }
 
 $(() => {
   const selectors = {
-    country: '.js-opc-address-form .js-country',
-    address: '.js-opc-address-form',
+    address: OPC_ADDRESSES_SECTION_SELECTOR,
   };
 
   handleOpcCountryChange(selectors);
diff --git a/views/js/opc-carrier-list.js b/views/js/opc-carrier-list.js
new file mode 100644
index 0000000..c42da77
--- /dev/null
+++ b/views/js/opc-carrier-list.js
@@ -0,0 +1,202 @@
+import OPC_EVENTS from './events';
+import OPC_SELECTORS from './selectors';
+import {getAjaxErrorResponse, getConfiguredOpcUrl, normalizeErrorResponse, updateCartSummary} from './runtime/opc-runtime';
+
+/**
+ * Copyright since 2007 PrestaShop SA and Contributors
+ * PrestaShop is an International Registered Trademark & Property of PrestaShop SA
+ */
+(function psOpcCarrierListRuntime() {
+const $ = window.$ || window.jQuery;
+const prestashop = window.prestashop || {};
+
+if (!$) {
+  return;
+}
+
+const CONTAINER_SELECTOR = OPC_SELECTORS.opc.deliveryMethods;
+const URL_KEY = 'carriers';
+const CHECKOUT_FORM_SELECTOR = OPC_SELECTORS.opc.checkout;
+const FAILED_EVENT_NAME = OPC_EVENTS.opcCarriersFailed;
+let selectedDeliveryAddressId = null;
+
+function getTemplateHtml(templateId) {
+  const template = document.querySelector(`#${templateId}`);
+
+  return template ? template.innerHTML : '';
+}
+
+function getCheckoutForm() {
+  return document.querySelector(CHECKOUT_FORM_SELECTOR);
+}
+
+function getSelectedSavedDeliveryAddressId() {
+  const selectedRadio = document.querySelector(
+    `${OPC_SELECTORS.opc.deliveryList} ${OPC_SELECTORS.opc.addressRadio}[name="id_address_delivery"]:checked`
+  );
+  const selectedAddressId = selectedRadio ? String(selectedRadio.getAttribute('value') || '') : '';
+
+  if (!selectedAddressId || selectedAddressId === 'new_address') {
+    return '';
+  }
+
+  return selectedAddressId;
+}
+
+function getFormValue(form, name) {
+  const direct = form.querySelector(`[name="${name}"]`);
+  const prefixed = form.querySelector(`[name="delivery_${name}"]`);
+
+  return ((direct && direct.value) || (prefixed && prefixed.value) || '').trim();
+}
+
+function buildCarriersUrl(baseUrl) {
+  const form = getCheckoutForm();
+
+  if (!form || !baseUrl) {
+    return '';
+  }
+
+  if (selectedDeliveryAddressId) {
+    const url = new URL(baseUrl, window.location.origin);
+
+    url.searchParams.set('id_address_delivery', selectedDeliveryAddressId);
+
+    return url.toString();
+  }
+
+  const deliveryMethodsContainer = document.querySelector(CONTAINER_SELECTOR);
+  const idCountry = getFormValue(form, 'id_country');
+  if (!idCountry) {
+    return '';
+  }
+
+  const url = new URL(baseUrl, window.location.origin);
+  const selectedSavedDeliveryAddressId = getSelectedSavedDeliveryAddressId();
+
+  url.searchParams.set('id_country', idCountry);
+
+  if (selectedSavedDeliveryAddressId) {
+    url.searchParams.set('id_address_delivery', selectedSavedDeliveryAddressId);
+  }
+
+  const postcode = getFormValue(form, 'postcode');
+  const idState = getFormValue(form, 'id_state');
+  const city = getFormValue(form, 'city');
+
+  if (postcode) {
+    url.searchParams.set('postcode', postcode);
+  }
+  if (idState) {
+    url.searchParams.set('id_state', idState);
+  }
+  if (city) {
+    url.searchParams.set('city', city);
+  }
+
+  return url.toString();
+}
+
+function fetchCarriers() {
+  const carriersUrl = buildCarriersUrl(getConfiguredOpcUrl(URL_KEY));
+  const $container = $(CONTAINER_SELECTOR);
+
+  if (!carriersUrl || !$container.length) {
+    return;
+  }
+
+  $container.html(getTemplateHtml(OPC_SELECTORS.templates.carrierLoader.replace('#', '')));
+  prestashop.emit(OPC_EVENTS.opcCarriersLoading, {});
+
+  $.get(carriersUrl)
+    .done((response) => {
+      if (!response || response.success === false) {
+        const resp = normalizeErrorResponse(response, 'Unable to load delivery methods.');
+        $container.html(getTemplateHtml(OPC_SELECTORS.templates.carrierError.replace('#', '')));
+        prestashop.emit(FAILED_EVENT_NAME, {resp});
+        prestashop.emit('handleError', {eventType: 'opcCarriers', resp});
+        return;
+      }
+
+      $container.html(response.carriers_html || '');
+      if (typeof response.id_address_delivery !== 'undefined') {
+        if (response.id_address_delivery) {
+          $container.attr('data-id-address', String(response.id_address_delivery));
+        } else {
+          $container.removeAttr('data-id-address');
+        }
+      }
+      if (response.preview) {
+        updateCartSummary(response.preview, response.totals);
+      }
+      prestashop.emit(OPC_EVENTS.opcCarriersUpdated, response);
+
+      const checkedCarrier = $container.find(`${OPC_SELECTORS.inputs.deliveryOption}:checked`).get(0);
+      if (checkedCarrier) {
+        $container.attr('data-confirmed-delivery-option', String(checkedCarrier.value || ''));
+        prestashop.emit(OPC_EVENTS.opcCarrierSelected, {
+          carrierId: checkedCarrier.value,
+          resp: response,
+        });
+      } else {
+        $container.removeAttr('data-confirmed-delivery-option');
+      }
+    })
+    .fail((jqXHR) => {
+      const resp = getAjaxErrorResponse(jqXHR, 'Unable to load delivery methods.');
+      $container.html(getTemplateHtml(OPC_SELECTORS.templates.carrierError.replace('#', '')));
+      prestashop.emit(FAILED_EVENT_NAME, {resp});
+      prestashop.emit('handleError', {eventType: 'opcCarriers', resp});
+    });
+}
+
+$(function () {
+  const form = getCheckoutForm();
+
+  if (!form) {
+    return;
+  }
+
+  fetchCarriers();
+});
+
+$(document).on('click', '[data-opc-action="retry-carriers"]', (event) => {
+  event.preventDefault();
+  fetchCarriers();
+});
+
+prestashop.on(OPC_EVENTS.opcCarriersRetry, fetchCarriers);
+
+prestashop.on(OPC_EVENTS.opcDeliveryAddressUpdated, () => {
+  const deliveryMethodsContainer = document.querySelector(CONTAINER_SELECTOR);
+  const selectedSavedDeliveryAddressId = getSelectedSavedDeliveryAddressId();
+
+  if (selectedSavedDeliveryAddressId) {
+    selectedDeliveryAddressId = selectedSavedDeliveryAddressId;
+    if (deliveryMethodsContainer) {
+      deliveryMethodsContainer.setAttribute('data-id-address', selectedSavedDeliveryAddressId);
+    }
+
+    fetchCarriers();
+    return;
+  }
+
+  selectedDeliveryAddressId = null;
+  if (deliveryMethodsContainer) {
+    deliveryMethodsContainer.removeAttribute('data-id-address');
+  }
+
+  fetchCarriers();
+});
+
+prestashop.on(OPC_EVENTS.opcDeliveryAddressSelected, ({idAddress}) => {
+  selectedDeliveryAddressId = String(idAddress || '');
+  fetchCarriers();
+});
+
+const deliveryMethodsContainer = document.querySelector(CONTAINER_SELECTOR);
+const initiallySelectedSavedDeliveryAddressId = getSelectedSavedDeliveryAddressId();
+if (deliveryMethodsContainer && initiallySelectedSavedDeliveryAddressId) {
+  selectedDeliveryAddressId = initiallySelectedSavedDeliveryAddressId;
+}
+}());
diff --git a/views/js/opc-carrier-select.js b/views/js/opc-carrier-select.js
new file mode 100644
index 0000000..c40de7d
--- /dev/null
+++ b/views/js/opc-carrier-select.js
@@ -0,0 +1,126 @@
+import OPC_EVENTS from './events';
+import OPC_SELECTORS from './selectors';
+import {getAjaxErrorResponse, getConfiguredOpcUrl, normalizeErrorResponse, updateCartSummary} from './runtime/opc-runtime';
+
+/**
+ * Copyright since 2007 PrestaShop SA and Contributors
+ * PrestaShop is an International Registered Trademark & Property of PrestaShop SA
+ */
+(function psOpcCarrierSelectRuntime() {
+const $ = window.$ || window.jQuery;
+const prestashop = window.prestashop || {};
+
+if (!$) {
+  return;
+}
+
+const CONTAINER_SELECTOR = OPC_SELECTORS.opc.deliveryMethods;
+const URL_KEY = 'selectCarrier';
+const CHECKOUT_FORM_SELECTOR = OPC_SELECTORS.opc.checkout;
+const DELIVERY_ADDRESS_SECTION_SELECTOR = OPC_SELECTORS.opc.deliverySection;
+const CONFIRMED_DELIVERY_OPTION_ATTRIBUTE = 'data-confirmed-delivery-option';
+
+function getDeliveryAddressSection() {
+  return document.querySelector(DELIVERY_ADDRESS_SECTION_SELECTOR);
+}
+
+function collectAddressFields() {
+  const form = document.querySelector(CHECKOUT_FORM_SELECTOR);
+  if (!form) {
+    return {};
+  }
+
+  const scope = getDeliveryAddressSection() || form;
+
+  return ['id_country', 'postcode', 'id_state', 'city'].reduce((payload, field) => {
+    const direct = scope.querySelector(`[name="${field}"]`);
+    const prefixed = scope.querySelector(`[name="delivery_${field}"]`);
+    const value = ((direct && direct.value) || (prefixed && prefixed.value) || '').trim();
+
+    if (value === '') {
+      return payload;
+    }
+
+    return {
+      ...payload,
+      [field]: value,
+    };
+  }, {});
+}
+
+function findDeliveryOptionRadio($container, deliveryOption) {
+  return $container.find(OPC_SELECTORS.inputs.deliveryOption).filter((_, input) => {
+    return String($(input).val() || '') === deliveryOption;
+  }).first();
+}
+
+function setConfirmedDeliveryOption($container, deliveryOption) {
+  if (!deliveryOption) {
+    $container.removeAttr(CONFIRMED_DELIVERY_OPTION_ATTRIBUTE);
+
+    return;
+  }
+
+  $container.attr(CONFIRMED_DELIVERY_OPTION_ATTRIBUTE, deliveryOption);
+}
+
+function restoreConfirmedDeliveryOption($container) {
+  const confirmedDeliveryOption = String($container.attr(CONFIRMED_DELIVERY_OPTION_ATTRIBUTE) || '');
+
+  if (!confirmedDeliveryOption) {
+    return;
+  }
+
+  const $confirmedRadio = findDeliveryOptionRadio($container, confirmedDeliveryOption);
+  if (!$confirmedRadio.length) {
+    return;
+  }
+
+  $confirmedRadio.prop('checked', true);
+}
+
+$(document).on('change', `${CONTAINER_SELECTOR} ${OPC_SELECTORS.inputs.deliveryOption}`, (event) => {
+  const $radio = $(event.currentTarget);
+  const $container = $(CONTAINER_SELECTOR);
+  const selectCarrierUrl = getConfiguredOpcUrl(URL_KEY);
+  const deliveryOption = String($radio.val() || '');
+
+  if (!selectCarrierUrl || !deliveryOption) {
+    prestashop.emit('handleError', {
+      eventType: 'opcSelectCarrier',
+      resp: normalizeErrorResponse(null, 'Missing OPC carrier selection payload.'),
+    });
+    return;
+  }
+
+  const payload = {
+    delivery_option: deliveryOption,
+    ...($container.attr('data-id-address') ? {} : collectAddressFields()),
+  };
+
+  $.post(selectCarrierUrl, payload)
+    .done((response) => {
+      if (!response || response.success === false) {
+        restoreConfirmedDeliveryOption($container);
+        prestashop.emit('handleError', {
+          eventType: 'opcSelectCarrier',
+          resp: normalizeErrorResponse(response, 'Unable to select the delivery method.'),
+        });
+        return;
+      }
+
+      if (response.preview) {
+        updateCartSummary(response.preview, response.totals);
+      }
+      setConfirmedDeliveryOption($container, deliveryOption);
+      prestashop.emit(OPC_EVENTS.opcCarrierSelected, response);
+    })
+    .fail((jqXHR) => {
+      restoreConfirmedDeliveryOption($container);
+      prestashop.emit('handleError', {
+        eventType: 'opcSelectCarrier',
+        resp: getAjaxErrorResponse(jqXHR, 'Unable to select the delivery method.'),
+      });
+    });
+});
+}());
diff --git a/views/js/opc-guest-init.js b/views/js/opc-guest-init.js
index 4a1702a..0953775 100644
--- a/views/js/opc-guest-init.js
+++ b/views/js/opc-guest-init.js
@@ -1,3 +1,7 @@
+import OPC_EVENTS from './events';
+import OPC_SELECTORS from './selectors';
+import {getConfiguredOpcUrl} from './runtime/opc-runtime';
+
 /**
  * Copyright since 2007 PrestaShop SA and Contributors
  * PrestaShop is an International Registered Trademark & Property of PrestaShop SA
@@ -30,10 +34,12 @@ const prestashop = window.prestashop || {};
 
 const CREATE_DEBOUNCE_MS = 250;
 const UPDATE_DEBOUNCE_MS = 900;
-const OPC_FORM_SELECTOR = '.one-page-checkout';
-const OPC_ADDRESS_FORM_SELECTOR = '.js-opc-address-form';
-const EMAIL_FIELD_SELECTOR = 'input[name="email"]';
+const OPC_FORM_SELECTOR = OPC_SELECTORS.opc.checkout;
+const OPC_CONTACT_SECTION_SELECTOR = OPC_SELECTORS.opc.contactSection;
+const EMAIL_FIELD_SELECTOR = OPC_SELECTORS.inputs.email;
+const INPUT_FIELD_SELECTOR = 'input, select, textarea';
 const CHECKBOX_FIELD_SELECTOR = 'input[type="checkbox"]';
+const ADDRESS_MODAL_SELECTOR = OPC_SELECTORS.modals.address;
 const REQUEST_COMPLETED = 4;
 const MODULE_GUEST_INIT_URL_KEY = 'guestInit';
 
@@ -50,7 +56,7 @@ let isFinalSubmitInProgress = false;
  * @property {string} [token]
  * @property {string} [static_token]
  *
- * Additional checkbox fields are sent as `'1'` / `'0'`.
+ * Additional personal-information fields are serialized when relevant.
  */
 
 /**
@@ -63,24 +69,6 @@ let isFinalSubmitInProgress = false;
  * @property {string} [static_token]
  */
 
-function getOpcRuntimeConfiguration() {
-  if (!window || typeof window.ps_onepagecheckout !== 'object' || !window.ps_onepagecheckout) {
-    return null;
-  }
-
-  return window.ps_onepagecheckout;
-}
-
-function getConfiguredOpcUrl(urlKey) {
-  const runtimeConfiguration = getOpcRuntimeConfiguration();
-
-  if (runtimeConfiguration && runtimeConfiguration.urls && runtimeConfiguration.urls[urlKey]) {
-    return String(runtimeConfiguration.urls[urlKey]);
-  }
-
-  return '';
-}
-
 function getCustomerIdFromContext() {
   const {customer} = prestashop;
 
@@ -141,8 +129,12 @@ function isGuestUpdateMode() {
   return guestCustomerId > 0 || hasPersistedGuestContext();
 }
 
-function getOpcAddressContainer() {
-  return $(OPC_ADDRESS_FORM_SELECTOR).first();
+function getOpcContactContainer() {
+  return $(OPC_CONTACT_SECTION_SELECTOR).first();
+}
+
+function isFieldInsideAddressModal(element) {
+  return $(element).closest(ADDRESS_MODAL_SELECTOR).length > 0;
 }
 
 function getEmailField($container) {
@@ -160,7 +152,7 @@ function isGuestInitApplicable() {
     return false;
   }
 
-  return $(OPC_FORM_SELECTOR).length > 0 && getOpcAddressContainer().length > 0;
+  return $(OPC_FORM_SELECTOR).length > 0 && getOpcContactContainer().length > 0;
 }
 
 function isEmailValid($emailField) {
@@ -201,14 +193,32 @@ function collectPayload($container) {
     payload.static_token = securityToken;
   }
 
-  $container.find(CHECKBOX_FIELD_SELECTOR).each((_, checkbox) => {
-    const fieldName = checkbox.name;
+  $container.find(INPUT_FIELD_SELECTOR).each((_, element) => {
+    const fieldName = element.name;
+    const inputType = String(element.type || '').toLowerCase();
+
+    if (!fieldName || fieldName === 'email' || element.disabled || isFieldInsideAddressModal(element)) {
+      return;
+    }
+
+    if (['hidden', 'submit', 'button', 'image', 'reset', 'file'].includes(inputType)) {
+      return;
+    }
 
-    if (!fieldName) {
+    if (inputType === 'checkbox') {
+      payload[fieldName] = element.checked ? '1' : '0';
       return;
     }
 
-    payload[fieldName] = checkbox.checked ? '1' : '0';
+    if (inputType === 'radio') {
+      if (element.checked) {
+        payload[fieldName] = String(element.value || '');
+      }
+
+      return;
+    }
+
+    payload[fieldName] = String($(element).val() || '').trim();
   });
 
   return payload;
@@ -220,7 +230,7 @@ function collectRequiredCheckboxState($container) {
   $container.find(`${CHECKBOX_FIELD_SELECTOR}[required]`).each((_, checkbox) => {
     const fieldName = checkbox.name;
 
-    if (!fieldName) {
+    if (!fieldName || isFieldInsideAddressModal(checkbox)) {
       return;
     }
 
@@ -247,7 +257,7 @@ function setInitialGuestEmailFingerprint() {
     return;
   }
 
-  const $container = getOpcAddressContainer();
+  const $container = getOpcContactContainer();
   const $emailField = getEmailField($container);
 
   if (!isEmailValid($emailField)) {
@@ -273,6 +283,14 @@ function stopGuestInitForFinalSubmit() {
   }
 }
 
+function abortPendingGuestInit() {
+  pendingFingerprint = '';
+
+  if (inFlightRequest && inFlightRequest.readyState !== REQUEST_COMPLETED) {
+    inFlightRequest.abort();
+  }
+}
+
 function tryGuestInit() {
   if (isFinalSubmitInProgress) {
     return;
@@ -282,10 +300,11 @@ function tryGuestInit() {
     return;
   }
 
-  const $container = getOpcAddressContainer();
+  const $container = getOpcContactContainer();
   const $emailField = getEmailField($container);
 
   if (!isEmailValid($emailField)) {
+    abortPendingGuestInit();
     return;
   }
 
@@ -294,6 +313,7 @@ function tryGuestInit() {
   const guestUpdateMode = isGuestUpdateMode();
 
   if (!guestUpdateMode && hasMissingRequiredConsent(requiredCheckboxState)) {
+    abortPendingGuestInit();
     return;
   }
 
@@ -344,12 +364,17 @@ function tryGuestInit() {
 
         if (responseCustomerId > 0) {
           guestCustomerId = responseCustomerId;
+          if (window.prestashop) {
+            window.prestashop.customer = window.prestashop.customer || {};
+            window.prestashop.customer.id = responseCustomerId;
+            prestashop.customer = window.prestashop.customer;
+          }
           // Once guest identity exists, dedupe on email only and ignore checkbox toggles.
           lastSubmittedFingerprint = getPayloadFingerprint({email: payload.email});
         } else {
           lastSubmittedFingerprint = payloadFingerprint;
         }
-        prestashop.emit('opcGuestInitSuccess', {resp});
+        prestashop.emit(OPC_EVENTS.opcGuestInitSuccess, {resp});
       } else if (resp && resp.errors && Array.isArray(resp.errors.token) && resp.errors.token.length > 0) {
         // Token errors need fresh context, avoid retry loops while payload stays unchanged.
         lastSubmittedFingerprint = payloadFingerprint;
@@ -389,18 +414,19 @@ $(() => {
 
   setInitialGuestEmailFingerprint();
 
-  $('body').on('input change', `${OPC_ADDRESS_FORM_SELECTOR} ${EMAIL_FIELD_SELECTOR}`, () => {
+  $('body').on('input change', `${OPC_CONTACT_SECTION_SELECTOR} ${EMAIL_FIELD_SELECTOR}`, () => {
     scheduleGuestInit();
   });
 
-  $('body').on('change', `${OPC_ADDRESS_FORM_SELECTOR} ${CHECKBOX_FIELD_SELECTOR}`, () => {
-    scheduleGuestInit();
-  });
+  $('body').on('change', `${OPC_CONTACT_SECTION_SELECTOR} ${INPUT_FIELD_SELECTOR}`, (event) => {
+    if (isFieldInsideAddressModal(event.currentTarget)) {
+      return;
+    }
 
-  prestashop.on('updatedOpcAddressForm', () => {
     scheduleGuestInit();
   });
-  prestashop.on('opcFinalSubmitStarted', () => {
+
+  prestashop.on(OPC_EVENTS.opcFinalSubmitStarted, () => {
     stopGuestInitForFinalSubmit();
   });
 
diff --git a/views/js/opc-payment-list.js b/views/js/opc-payment-list.js
new file mode 100644
index 0000000..d438b13
--- /dev/null
+++ b/views/js/opc-payment-list.js
@@ -0,0 +1,163 @@
+import OPC_EVENTS from './events';
+import OPC_SELECTORS from './selectors';
+import {getAjaxErrorResponse, getConfiguredOpcUrl, normalizeErrorResponse} from './runtime/opc-runtime';
+
+/**
+ * Copyright since 2007 PrestaShop SA and Contributors
+ * PrestaShop is an International Registered Trademark & Property of PrestaShop SA
+ */
+(function psOpcPaymentListRuntime() {
+const $ = window.$ || window.jQuery;
+const prestashop = window.prestashop || {};
+
+if (!$) {
+  return;
+}
+
+const CONTAINER_SELECTOR = OPC_SELECTORS.opc.paymentMethods;
+const CHECKOUT_FORM_SELECTOR = OPC_SELECTORS.opc.checkout;
+const URL_KEY = 'paymentMethods';
+let fetchGeneration = 0;
+
+function getTemplateHtml(templateId) {
+  const template = document.querySelector(`#${templateId}`);
+
+  return template ? template.innerHTML : '';
+}
+
+function getContainer() {
+  return $(CONTAINER_SELECTOR);
+}
+
+function getCheckoutForm() {
+  return document.querySelector(CHECKOUT_FORM_SELECTOR);
+}
+
+function getSelectedSavedAddressId(listSelector, radioName) {
+  const selectedRadio = document.querySelector(
+    `${listSelector} ${OPC_SELECTORS.opc.addressRadio}[name="${radioName}"]:checked`
+  );
+  const selectedAddressId = selectedRadio ? String(selectedRadio.getAttribute('value') || '') : '';
+
+  if (!selectedAddressId || selectedAddressId === 'new_address') {
+    return '';
+  }
+
+  return selectedAddressId;
+}
+
+function setLoading() {
+  const $container = getContainer();
+  if (!$container.length) {
+    return;
+  }
+
+  $container.html(getTemplateHtml(OPC_SELECTORS.templates.paymentLoader.replace('#', '')));
+  prestashop.emit(OPC_EVENTS.opcPaymentMethodsLoading, {});
+}
+
+function buildPaymentMethodsUrl(baseUrl) {
+  const form = getCheckoutForm();
+
+  if (!form || !baseUrl) {
+    return '';
+  }
+
+  const url = new URL(baseUrl, window.location.origin);
+  const idCountry = form.querySelector('[name="id_country"]')?.value
+    || form.querySelector('[name="delivery_id_country"]')?.value
+    || '';
+  const invoiceIdCountry = form.querySelector('[name="invoice_id_country"]')?.value || '';
+  const deliveryAddressId = getSelectedSavedAddressId(OPC_SELECTORS.opc.deliveryList, 'id_address_delivery')
+    || form.querySelector('[name="id_address_delivery"]')?.value
+    || '';
+  const invoiceAddressId = getSelectedSavedAddressId(OPC_SELECTORS.opc.billingList, 'id_address_invoice')
+    || form.querySelector('[name="id_address_invoice"]')?.value
+    || '';
+
+  if (idCountry) {
+    url.searchParams.set('id_country', idCountry);
+  }
+
+  if (invoiceIdCountry) {
+    url.searchParams.set('invoice_id_country', invoiceIdCountry);
+  }
+
+  if (deliveryAddressId) {
+    url.searchParams.set('id_address_delivery', deliveryAddressId);
+  }
+
+  if (invoiceAddressId) {
+    url.searchParams.set('id_address_invoice', invoiceAddressId);
+  }
+
+  return url.toString();
+}
+
+function fetchPaymentMethods() {
+  const $container = getContainer();
+  const paymentMethodsUrl = buildPaymentMethodsUrl(getConfiguredOpcUrl(URL_KEY));
+
+  if (!$container.length || !paymentMethodsUrl) {
+    return;
+  }
+
+  const generation = ++fetchGeneration;
+  setLoading();
+
+  $.get(paymentMethodsUrl)
+    .done((response) => {
+      if (generation !== fetchGeneration) {
+        return;
+      }
+
+      if (!response || response.success === false) {
+        const error = normalizeErrorResponse(response, 'Unable to load payment methods.');
+        $container.html(getTemplateHtml(OPC_SELECTORS.templates.paymentError.replace('#', '')));
+        prestashop.emit(OPC_EVENTS.opcPaymentMethodsFailed, {error});
+        prestashop.emit('handleError', {eventType: 'opcPaymentMethods', resp: error});
+
+        return;
+      }
+
+      $container.html(response.payment_html || '');
+      prestashop.emit(OPC_EVENTS.opcPaymentMethodsUpdated, response);
+    })
+    .fail((jqXHR) => {
+      if (generation !== fetchGeneration) {
+        return;
+      }
+
+      const error = getAjaxErrorResponse(jqXHR, 'Unable to load payment methods.');
+      $container.html(getTemplateHtml(OPC_SELECTORS.templates.paymentError.replace('#', '')));
+      prestashop.emit(OPC_EVENTS.opcPaymentMethodsFailed, {error});
+      prestashop.emit('handleError', {eventType: 'opcPaymentMethods', resp: error});
+    });
+}
+
+$(fetchPaymentMethods);
+$(document).on('click', '[data-opc-action="retry-payment"]', (event) => {
+  event.preventDefault();
+  fetchPaymentMethods();
+});
+
+prestashop.on(OPC_EVENTS.opcCarrierSelected, fetchPaymentMethods);
+prestashop.on(OPC_EVENTS.opcBillingAddressUpdated, fetchPaymentMethods);
+prestashop.on(OPC_EVENTS.opcGuestInitSuccess, fetchPaymentMethods);
+prestashop.on(OPC_EVENTS.opcPaymentMethodsRetry, fetchPaymentMethods);
+prestashop.on(OPC_EVENTS.opcCarriersLoading, () => {
+  fetchGeneration += 1;
+  setLoading();
+});
+
+prestashop.on(OPC_EVENTS.opcCarriersFailed, () => {
+  const $container = getContainer();
+
+  fetchGeneration += 1;
+  if ($container.length) {
+    $container.html(getTemplateHtml(OPC_SELECTORS.templates.paymentError.replace('#', '')));
+  }
+
+  prestashop.emit(OPC_EVENTS.opcPaymentMethodsFailed, {error: 'carrier fetch failed'});
+});
+}());
diff --git a/views/js/opc-payment-select.js b/views/js/opc-payment-select.js
new file mode 100644
index 0000000..200f939
--- /dev/null
+++ b/views/js/opc-payment-select.js
@@ -0,0 +1,168 @@
+import OPC_EVENTS from './events';
+import OPC_SELECTORS from './selectors';
+import {getAjaxErrorResponse, getConfiguredOpcUrl, normalizeErrorResponse} from './runtime/opc-runtime';
+
+/**
+ * Copyright since 2007 PrestaShop SA and Contributors
+ * PrestaShop is an International Registered Trademark & Property of PrestaShop SA
+ */
+(function psOpcPaymentSelectRuntime() {
+const $ = window.$ || window.jQuery;
+const prestashop = window.prestashop || {};
+
+if (!$) {
+  return;
+}
+
+const CONTAINER_SELECTOR = OPC_SELECTORS.opc.paymentMethods;
+const URL_KEY = 'selectPayment';
+const EVENT_NAME = OPC_EVENTS.opcPaymentMethodSelected;
+const CONFIRMED_OPTION_ATTRIBUTE = 'data-confirmed-payment-option-id';
+const CONFIRMED_MODULE_ATTRIBUTE = 'data-confirmed-payment-module';
+const CONFIRMED_SELECTION_KEY_ATTRIBUTE = 'data-confirmed-payment-selection-key';
+
+function togglePaymentPanels($container, paymentOptionId) {
+  $container.find('.js-additional-information, .js-payment-option-form').hide();
+  $container.find('.js-payment-option-input').prop('disabled', true);
+  $container.find(OPC_SELECTORS.inputs.paymentOption).each((_, input) => {
+    const $input = $(input);
+    const isSelectedOption = String($input.val() || '') === paymentOptionId;
+
+    $input.prop('checked', isSelectedOption);
+
+    if (isSelectedOption) {
+      $container.find(`#${paymentOptionId}-additional-information`).show();
+      $container.find(`#pay-with-${paymentOptionId}-form`).show();
+      $container.find(`#pay-with-${paymentOptionId}-form .js-payment-option-input`).prop('disabled', false);
+    }
+  });
+}
+
+function clearPaymentPanels($container) {
+  $container.find('.js-additional-information, .js-payment-option-form').hide();
+  $container.find('.js-payment-option-input').prop('disabled', true);
+  $container.find(OPC_SELECTORS.inputs.paymentOption).prop('checked', false);
+}
+
+function setConfirmedPaymentSelection($container, paymentOptionId, paymentModuleName, paymentSelectionKey) {
+  if (paymentOptionId) {
+    $container.attr(CONFIRMED_OPTION_ATTRIBUTE, paymentOptionId);
+  } else {
+    $container.removeAttr(CONFIRMED_OPTION_ATTRIBUTE);
+  }
+
+  if (paymentModuleName) {
+    $container.attr(CONFIRMED_MODULE_ATTRIBUTE, paymentModuleName);
+  } else {
+    $container.removeAttr(CONFIRMED_MODULE_ATTRIBUTE);
+  }
+
+  if (paymentSelectionKey) {
+    $container.attr(CONFIRMED_SELECTION_KEY_ATTRIBUTE, paymentSelectionKey);
+  } else {
+    $container.removeAttr(CONFIRMED_SELECTION_KEY_ATTRIBUTE);
+  }
+}
+
+function restoreConfirmedPaymentSelection($container) {
+  const confirmedPaymentOptionId = String($container.attr(CONFIRMED_OPTION_ATTRIBUTE) || '');
+
+  if (confirmedPaymentOptionId) {
+    togglePaymentPanels($container, confirmedPaymentOptionId);
+
+    return;
+  }
+
+  clearPaymentPanels($container);
+}
+
+$(document).on('change', `${CONTAINER_SELECTOR} ${OPC_SELECTORS.inputs.paymentOption}`, (event) => {
+  const $radio = $(event.currentTarget);
+  const paymentOptionId = String($radio.val() || '');
+  const paymentModuleName = String($radio.data('moduleName') || $radio.data('module-name') || '');
+  const paymentSelectionKey = String($radio.data('selectionKey') || $radio.data('selection-key') || '');
+  const selectPaymentUrl = getConfiguredOpcUrl(URL_KEY);
+  const $container = $(CONTAINER_SELECTOR);
+
+  if (!selectPaymentUrl || !paymentOptionId || !paymentModuleName || !paymentSelectionKey) {
+    prestashop.emit('handleError', {
+      eventType: 'opcSelectPayment',
+      resp: normalizeErrorResponse(null, 'Missing OPC payment selection payload.'),
+    });
+
+    return;
+  }
+
+  togglePaymentPanels($container, paymentOptionId);
+
+  $.post(selectPaymentUrl, {
+    payment_option: paymentOptionId,
+    payment_module: paymentModuleName,
+    payment_selection_key: paymentSelectionKey,
+  })
+    .done((response) => {
+      if (!response || response.success === false) {
+        restoreConfirmedPaymentSelection($container);
+        prestashop.emit('handleError', {
+          eventType: 'opcSelectPayment',
+          resp: normalizeErrorResponse(response, 'Unable to select the payment method.'),
+        });
+
+        return;
+      }
+
+      setConfirmedPaymentSelection($container, paymentOptionId, paymentModuleName, paymentSelectionKey);
+
+      prestashop.emit(EVENT_NAME, {
+        paymentOptionId,
+        paymentModule: paymentModuleName,
+        paymentSelectionKey,
+        resp: response,
+      });
+    })
+    .fail((jqXHR) => {
+      restoreConfirmedPaymentSelection($container);
+      prestashop.emit('handleError', {
+        eventType: 'opcSelectPayment',
+        resp: getAjaxErrorResponse(jqXHR, 'Unable to select the payment method.'),
+      });
+    });
+});
+
+prestashop.on(OPC_EVENTS.opcPaymentMethodsUpdated, (response) => {
+  const selectedSelectionKey = String((response && response.selected_payment_selection_key) || '');
+  const selectedModule = String((response && response.selected_payment_module) || '');
+  const $container = $(CONTAINER_SELECTOR);
+
+  if (selectedSelectionKey) {
+    const $selectedRadio = $container.find(`${OPC_SELECTORS.inputs.paymentOption}[data-selection-key="${selectedSelectionKey}"]`).first();
+
+    if ($selectedRadio.length) {
+      const selectedPaymentOptionId = String($selectedRadio.val() || '');
+      const selectedModuleName = String($selectedRadio.data('moduleName') || $selectedRadio.data('module-name') || '');
+
+      togglePaymentPanels($container, selectedPaymentOptionId);
+      setConfirmedPaymentSelection($container, selectedPaymentOptionId, selectedModuleName, selectedSelectionKey);
+
+      return;
+    }
+  }
+
+  if (!selectedModule) {
+    return;
+  }
+
+  const $selectedRadio = $container.find(`${OPC_SELECTORS.inputs.paymentOption}[data-module-name="${selectedModule}"]`).first();
+
+  if (!$selectedRadio.length) {
+    setConfirmedPaymentSelection($container, '', '', '');
+
+    return;
+  }
+
+  const selectedPaymentOptionId = String($selectedRadio.val() || '');
+
+  togglePaymentPanels($container, selectedPaymentOptionId);
+  setConfirmedPaymentSelection($container, selectedPaymentOptionId, selectedModule, String($selectedRadio.data('selectionKey') || $selectedRadio.data('selection-key') || ''));
+});
+}());
diff --git a/views/js/opc-submit.js b/views/js/opc-submit.js
new file mode 100644
index 0000000..7919cff
--- /dev/null
+++ b/views/js/opc-submit.js
@@ -0,0 +1,652 @@
+import OPC_EVENTS from './events';
+import OPC_SELECTORS from './selectors';
+import {getConfiguredOpcUrl, normalizeErrorResponse, updatePayAmount} from './runtime/opc-runtime';
+
+/**
+ * Copyright since 2007 PrestaShop SA and Contributors
+ * PrestaShop is an International Registered Trademark & Property of PrestaShop SA
+ *
+ * NOTICE OF LICENSE
+ *
+ * This source file is subject to the Open Software License (OSL 3.0)
+ * that is bundled with this package in the file LICENSE.md.
+ * It is also available through the world-wide-web at this URL:
+ * https://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to
+ * obtain it through the world-wide-web, please send an email
+ * to license@prestashop.com so we can send you a copy immediately.
+ *
+ * DISCLAIMER
+ *
+ * Do not edit or add to this file if you wish to upgrade PrestaShop to newer
+ * versions in the future. If you wish to customize PrestaShop for your
+ * needs please refer to https://devdocs.prestashop.com/ for more information.
+ *
+ * @author    PrestaShop SA and Contributors <contact@prestashop.com>
+ * @copyright Since 2007 PrestaShop SA and Contributors
+ * @license   https://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ */
+
+(function psOpcSubmitRuntime() {
+const $ = window.$ || window.jQuery;
+const prestashop = window.prestashop || null;
+
+if (!$ || !prestashop || typeof prestashop.on !== 'function') {
+  return;
+}
+
+const OPC_FORM_ID_SELECTOR = OPC_SELECTORS.opc.form;
+const CHECKOUT_SELECTOR = OPC_SELECTORS.opc.checkout;
+const PAY_BUTTON_SELECTOR = OPC_SELECTORS.opc.payButton;
+const BILLING_SECTION_SELECTOR = OPC_SELECTORS.opc.billingSection;
+const PAYMENT_METHODS_SELECTOR = OPC_SELECTORS.opc.paymentMethods;
+const DELIVERY_METHODS_SELECTOR = OPC_SELECTORS.opc.deliveryMethods;
+const CHECKOUT_FOOTER_SELECTOR = OPC_SELECTORS.opc.checkoutFooter;
+const USE_SAME_ADDRESS_SELECTOR = OPC_SELECTORS.opc.useSameAddress;
+const DELIVERY_OPTION_SELECTOR = OPC_SELECTORS.inputs.deliveryOption;
+const PAYMENT_OPTION_SELECTOR = OPC_SELECTORS.inputs.paymentOption;
+const PAYMENT_CONDITIONS_SELECTOR = OPC_SELECTORS.inputs.conditions;
+const OPC_SUBMIT_URL_KEY = 'opcSubmit';
+
+let billingToggleHandler = null;
+let paymentMethodsState = 'idle';
+let isFinalSubmitInFlight = false;
+
+function getCheckoutForm() {
+  return document.querySelector(OPC_FORM_ID_SELECTOR) || document.querySelector(CHECKOUT_SELECTOR);
+}
+
+function getPayButton() {
+  return document.querySelector(PAY_BUTTON_SELECTOR);
+}
+
+function getCheckoutFooter() {
+  return document.querySelector(CHECKOUT_FOOTER_SELECTOR) || document;
+}
+
+function getConditionsToApproveInputs() {
+  return Array.from(getCheckoutFooter().querySelectorAll('input[name^="conditions_to_approve"]'));
+}
+
+function appendConditionsToApproveToFormData(payload) {
+  getConditionsToApproveInputs().forEach((input) => {
+    if (!(input instanceof HTMLInputElement) || !input.name) {
+      return;
+    }
+
+    if (input.type === 'checkbox') {
+      if (input.checked) {
+        payload.set(input.name, input.value);
+      }
+
+      return;
+    }
+
+    if (String(input.value || '').trim() !== '') {
+      payload.set(input.name, input.value);
+    }
+  });
+}
+
+function isElementVisible(element) {
+  if (!(element instanceof HTMLElement)) {
+    return false;
+  }
+
+  const modal = element.closest('.modal');
+  if (modal instanceof HTMLElement && !modal.classList.contains('show')) {
+    return false;
+  }
+
+  const billingSection = element.closest(BILLING_SECTION_SELECTOR);
+  if (billingSection instanceof HTMLElement && window.getComputedStyle(billingSection).display === 'none') {
+    return false;
+  }
+
+  const computedStyle = window.getComputedStyle(element);
+
+  return computedStyle.display !== 'none'
+    && computedStyle.visibility !== 'hidden'
+    && element.getClientRects().length > 0;
+}
+
+function isRequiredFieldValid(field) {
+  if (!(field instanceof HTMLElement) || !isElementVisible(field)) {
+    return true;
+  }
+
+  if (field instanceof HTMLInputElement) {
+    if (field.type === 'checkbox') {
+      return field.checked;
+    }
+
+    if (field.type === 'radio') {
+      if (!field.name) {
+        return field.checked;
+      }
+
+      return Boolean(document.querySelector(`input[type="radio"][name="${field.name}"]:checked`));
+    }
+
+    return Boolean(field.value.trim());
+  }
+
+  if (field instanceof HTMLSelectElement || field instanceof HTMLTextAreaElement) {
+    return Boolean(String(field.value || '').trim());
+  }
+
+  return true;
+}
+
+function findCheckedPaymentOption(form) {
+  return form.querySelector(`${PAYMENT_OPTION_SELECTOR}:checked`)
+    || document.querySelector(`${PAYMENT_METHODS_SELECTOR} ${PAYMENT_OPTION_SELECTOR}:checked`)
+    || document.querySelector(`${PAYMENT_OPTION_SELECTOR}:checked`);
+}
+
+function getPaymentContainer() {
+  const paymentContainer = document.querySelector(PAYMENT_METHODS_SELECTOR);
+
+  return paymentContainer instanceof HTMLElement ? paymentContainer : null;
+}
+
+function arePaymentMethodsReady() {
+  const paymentMethods = document.querySelector(PAYMENT_METHODS_SELECTOR);
+
+  if (!(paymentMethods instanceof HTMLElement) || !isElementVisible(paymentMethods)) {
+    return true;
+  }
+
+  return paymentMethodsState !== 'loading' && paymentMethodsState !== 'failed';
+}
+
+function hasSelectedCarrier() {
+  const deliveryMethods = document.querySelector(DELIVERY_METHODS_SELECTOR);
+  const deliveryOptions = document.querySelectorAll(DELIVERY_OPTION_SELECTOR);
+
+  if (!(deliveryMethods instanceof HTMLElement) || !isElementVisible(deliveryMethods)) {
+    return true;
+  }
+
+  if (deliveryOptions.length === 0) {
+    return false;
+  }
+
+  return Boolean(deliveryMethods.querySelector(`${DELIVERY_OPTION_SELECTOR}:checked`));
+}
+
+function hasSelectedPayment() {
+  const paymentContainer = getPaymentContainer();
+
+  if (!(paymentContainer instanceof HTMLElement) || !isElementVisible(paymentContainer)) {
+    return true;
+  }
+
+  const paymentRadios = paymentContainer.querySelectorAll(PAYMENT_OPTION_SELECTOR);
+  if (paymentRadios.length === 0) {
+    return false;
+  }
+
+  return Boolean(paymentContainer.querySelector(`${PAYMENT_OPTION_SELECTOR}:checked`));
+}
+
+function validateForm() {
+  const form = getCheckoutForm();
+  const payButton = getPayButton();
+
+  if (!(form instanceof HTMLFormElement) || !(payButton instanceof HTMLButtonElement)) {
+    return;
+  }
+
+  const formFieldsAreValid = Array.from(form.querySelectorAll('[required]'))
+    .filter((field) => !(field instanceof HTMLInputElement && field.matches(PAYMENT_CONDITIONS_SELECTOR)))
+    .every((field) => isRequiredFieldValid(field));
+  const conditionsAreValid = getConditionsToApproveInputs().every((input) => {
+    if (!(input instanceof HTMLInputElement) || !input.required) {
+      return true;
+    }
+
+    if (input.type === 'checkbox') {
+      return input.checked;
+    }
+
+    return Boolean(String(input.value || '').trim());
+  });
+  const isValid = formFieldsAreValid
+    && conditionsAreValid
+    && hasSelectedCarrier()
+    && arePaymentMethodsReady()
+    && hasSelectedPayment();
+
+  payButton.disabled = !isValid;
+  prestashop.emit(OPC_EVENTS.opcFormValidated, {isValid});
+}
+
+function initBillingToggle() {
+  const useSameAddressField = document.querySelector(USE_SAME_ADDRESS_SELECTOR);
+  const billingSection = document.querySelector(BILLING_SECTION_SELECTOR);
+
+  if (!(useSameAddressField instanceof HTMLInputElement) || !(billingSection instanceof HTMLElement)) {
+    return;
+  }
+
+  if (billingToggleHandler) {
+    useSameAddressField.removeEventListener('change', billingToggleHandler);
+  }
+
+  billingToggleHandler = () => {
+    const isBillingVisible = !useSameAddressField.checked;
+
+    billingSection.style.display = isBillingVisible ? '' : 'none';
+    prestashop.emit(OPC_EVENTS.opcBillingSectionToggled, {visible: isBillingVisible});
+    validateForm();
+  };
+
+  useSameAddressField.addEventListener('change', billingToggleHandler);
+}
+
+function reportRequiredConditionsValidity() {
+  for (const input of getConditionsToApproveInputs()) {
+    if (!(input instanceof HTMLInputElement) || !input.required) {
+      continue;
+    }
+
+    if (input.checkValidity()) {
+      continue;
+    }
+
+    input.reportValidity();
+
+    return false;
+  }
+
+  return true;
+}
+
+function resolvePaymentSelection(form) {
+  const paymentContainer = getPaymentContainer();
+
+  if (!(paymentContainer instanceof HTMLElement) || !isElementVisible(paymentContainer)) {
+    return {
+      isValid: true,
+      paymentRadio: null,
+    };
+  }
+
+  const paymentRadios = paymentContainer.querySelectorAll(PAYMENT_OPTION_SELECTOR);
+  if (paymentRadios.length === 0) {
+    return {
+      isValid: true,
+      paymentRadio: null,
+    };
+  }
+
+  const selectedPayment = findCheckedPaymentOption(form);
+  if (selectedPayment instanceof HTMLInputElement) {
+    return {
+      isValid: true,
+      paymentRadio: selectedPayment,
+    };
+  }
+
+  paymentContainer.scrollIntoView({block: 'center', behavior: 'smooth'});
+  const firstPayment = paymentRadios[0];
+  if (firstPayment instanceof HTMLInputElement) {
+    firstPayment.focus();
+  }
+
+  return {
+    isValid: false,
+    paymentRadio: null,
+  };
+}
+
+function ajaxCheckCartStillOrderable() {
+  return $.post(`${window.prestashop.urls.pages.order}`, {
+    ajax: 1,
+    action: 'checkCartStillOrderable',
+  });
+}
+
+function emitSubmitFailure(response) {
+  prestashop.emit('handleError', {
+    eventType: 'opcSubmit',
+    resp: response,
+  });
+  prestashop.emit(OPC_EVENTS.opcSubmitFailed, {resp: response});
+}
+
+function emitSubmitRuntimeError(message) {
+  emitSubmitFailure(normalizeErrorResponse(null, message));
+}
+
+function submitPaymentModuleForm(paymentRadio) {
+  const optionId = paymentRadio.id;
+  const wrapper = document.querySelector(`#pay-with-${optionId}-form`);
+  const innerForm = wrapper ? wrapper.querySelector('form') : null;
+
+  prestashop.emit(OPC_EVENTS.opcFinalSubmitStarted);
+
+  if (innerForm instanceof HTMLFormElement) {
+    HTMLFormElement.prototype.submit.call(innerForm);
+
+    return;
+  }
+
+  emitSubmitRuntimeError('Missing rendered payment form for the selected option.');
+}
+
+function buildSubmitPayload(form, paymentRadio) {
+  const payload = new FormData(form);
+
+  appendConditionsToApproveToFormData(payload);
+
+  if (!payload.has('static_token')) {
+    const staticToken = window.prestashop?.static_token || window.prestashop?.token || '';
+
+    if (staticToken !== '') {
+      payload.set('static_token', staticToken);
+    }
+  }
+
+  if (paymentRadio instanceof HTMLInputElement && paymentRadio.dataset.moduleName) {
+    payload.set('paymentMethod', paymentRadio.dataset.moduleName);
+  }
+
+  return payload;
+}
+
+function validateNativeForm(form) {
+  if (!form.checkValidity()) {
+    form.reportValidity();
+
+    return false;
+  }
+
+  return true;
+}
+
+function ensureSubmitPreconditions(form) {
+  if (!validateNativeForm(form)) {
+    return {
+      isValid: false,
+      paymentRadio: null,
+    };
+  }
+
+  if (!reportRequiredConditionsValidity()) {
+    return {
+      isValid: false,
+      paymentRadio: null,
+    };
+  }
+
+  if (!arePaymentMethodsReady()) {
+    validateForm();
+
+    return {
+      isValid: false,
+      paymentRadio: null,
+    };
+  }
+
+  return resolvePaymentSelection(form);
+}
+
+function getOpcSubmitUrl() {
+  const submitUrl = getConfiguredOpcUrl(OPC_SUBMIT_URL_KEY);
+
+  if (submitUrl) {
+    return submitUrl;
+  }
+
+  emitSubmitRuntimeError('Missing OPC submit URL.');
+
+  return '';
+}
+
+async function fetchOpcSubmitResponse(submitUrl, payload) {
+  const rawResponse = await fetch(submitUrl, {
+    method: 'POST',
+    credentials: 'same-origin',
+    headers: {
+      Accept: 'application/json',
+    },
+    body: payload,
+  });
+
+  return rawResponse.json().catch(() => ({}));
+}
+
+function handleOpcSubmitFailure(response) {
+  if (response && response.reload) {
+    window.location.href = response.checkout_url || window.location.href;
+
+    return true;
+  }
+
+  emitSubmitFailure(response);
+
+  return true;
+}
+
+async function continueSuccessfulSubmit(response, paymentRadio) {
+  const checkResponse = await ajaxCheckCartStillOrderable();
+  const checkoutHandler = prestashop.checkout?.onCheckOrderableCartResponse;
+
+  if (typeof checkoutHandler === 'function') {
+    if (checkoutHandler(checkResponse, {})) {
+      return;
+    }
+  } else if (checkResponse && checkResponse.errors === true && checkResponse.cartUrl) {
+    window.location.href = checkResponse.cartUrl;
+
+    return;
+  }
+
+  if (paymentRadio instanceof HTMLInputElement) {
+    submitPaymentModuleForm(paymentRadio);
+
+    return;
+  }
+
+  window.location.href = response.checkout_url || window.prestashop.urls.pages.order;
+}
+
+async function submitOpcPay(form) {
+  if (isFinalSubmitInFlight) {
+    return;
+  }
+
+  const paymentSelection = ensureSubmitPreconditions(form);
+  if (!paymentSelection.isValid) {
+    return;
+  }
+
+  const submitUrl = getOpcSubmitUrl();
+  if (!submitUrl) {
+    return;
+  }
+
+  const payButton = getPayButton();
+  const payload = buildSubmitPayload(form, paymentSelection.paymentRadio);
+
+  isFinalSubmitInFlight = true;
+  if (payButton instanceof HTMLButtonElement) {
+    payButton.disabled = true;
+  }
+
+  try {
+    const response = await fetchOpcSubmitResponse(submitUrl, payload);
+
+    if (!response || response.success !== true) {
+      handleOpcSubmitFailure(response);
+      return;
+    }
+
+    await continueSuccessfulSubmit(response, paymentSelection.paymentRadio);
+  } catch (error) {
+    prestashop.emit('handleError', {
+      eventType: 'opcSubmit',
+      resp: {},
+    });
+    prestashop.emit(OPC_EVENTS.opcSubmitFailed, {error});
+  } finally {
+    isFinalSubmitInFlight = false;
+    validateForm();
+  }
+}
+
+function bindValidationListeners(form, payButton) {
+  if (!form.dataset.opcSubmitInputBound) {
+    form.addEventListener('input', validateForm);
+    form.dataset.opcSubmitInputBound = '1';
+  }
+
+  if (!form.dataset.opcSubmitChangeBound) {
+    form.addEventListener('change', validateForm);
+    form.dataset.opcSubmitChangeBound = '1';
+  }
+
+  if (!form.dataset.opcSubmitHandlerBound) {
+    form.addEventListener('submit', (event) => {
+      event.preventDefault();
+      submitOpcPay(form);
+    });
+    form.dataset.opcSubmitHandlerBound = '1';
+  }
+
+  if (!payButton.dataset.opcSubmitHandlerBound) {
+    payButton.addEventListener('click', (event) => {
+      event.preventDefault();
+
+      if (isFinalSubmitInFlight || payButton.disabled) {
+        return;
+      }
+
+      submitOpcPay(form);
+    });
+    payButton.dataset.opcSubmitHandlerBound = '1';
+  }
+}
+
+function bindChangeValidationListeners(root, selector, datasetKey) {
+  if (!(root instanceof HTMLElement || root instanceof HTMLFormElement)) {
+    return;
+  }
+
+  root.querySelectorAll(selector).forEach((element) => {
+    if (!(element instanceof HTMLInputElement) && !(element instanceof HTMLSelectElement) && !(element instanceof HTMLTextAreaElement)) {
+      return;
+    }
+
+    if (element.dataset[datasetKey] === '1') {
+      return;
+    }
+
+    element.addEventListener('change', validateForm);
+    element.dataset[datasetKey] = '1';
+  });
+}
+
+function bindScopedValidationListeners(form) {
+  bindChangeValidationListeners(form, DELIVERY_OPTION_SELECTOR, 'opcDeliveryValidationBound');
+
+  const paymentContainer = getPaymentContainer();
+  if (paymentContainer instanceof HTMLElement) {
+    bindChangeValidationListeners(paymentContainer, PAYMENT_OPTION_SELECTOR, 'opcPaymentValidationBound');
+  }
+
+  const checkoutFooter = getCheckoutFooter();
+  if (checkoutFooter instanceof HTMLElement || checkoutFooter instanceof Document) {
+    bindChangeValidationListeners(
+      checkoutFooter instanceof Document ? checkoutFooter.documentElement : checkoutFooter,
+      'input[name^="conditions_to_approve"]',
+      'opcConditionsValidationBound',
+    );
+  }
+}
+
+function bindCheckoutValidation() {
+  const form = getCheckoutForm();
+  const payButton = getPayButton();
+
+  if (!(form instanceof HTMLFormElement) || !(payButton instanceof HTMLButtonElement)) {
+    return;
+  }
+
+  bindValidationListeners(form, payButton);
+  bindScopedValidationListeners(form);
+}
+
+$(document).ready(() => {
+  const form = getCheckoutForm();
+  const payButton = getPayButton();
+
+  if (!(form instanceof HTMLFormElement) || !(payButton instanceof HTMLButtonElement)) {
+    return;
+  }
+
+  prestashop.on(OPC_EVENTS.opcFinalSubmitStarted, () => {
+    isFinalSubmitInFlight = true;
+  });
+
+  bindCheckoutValidation();
+  initBillingToggle();
+  validateForm();
+
+  prestashop.on(OPC_EVENTS.opcPaymentMethodsLoading, () => {
+    paymentMethodsState = 'loading';
+    validateForm();
+  });
+  prestashop.on(OPC_EVENTS.opcPaymentMethodsFailed, () => {
+    paymentMethodsState = 'failed';
+    bindScopedValidationListeners(form);
+    validateForm();
+  });
+  prestashop.on(OPC_EVENTS.opcPaymentMethodsUpdated, () => {
+    paymentMethodsState = 'ready';
+    bindScopedValidationListeners(form);
+    validateForm();
+  });
+  prestashop.on(OPC_EVENTS.opcDeliveryAddressUpdated, () => {
+    initBillingToggle();
+    bindScopedValidationListeners(form);
+    validateForm();
+  });
+  prestashop.on(OPC_EVENTS.opcBillingAddressUpdated, () => {
+    initBillingToggle();
+    bindScopedValidationListeners(form);
+    validateForm();
+  });
+  prestashop.on(OPC_EVENTS.opcCarriersUpdated, () => {
+    bindScopedValidationListeners(form);
+    validateForm();
+  });
+  prestashop.on(OPC_EVENTS.opcCarriersFailed, () => {
+    bindScopedValidationListeners(form);
+    validateForm();
+  });
+  prestashop.on('updatedCart', () => {
+    const totals = prestashop.cart && prestashop.cart.totals;
+    if (totals) {
+      updatePayAmount(totals);
+      return;
+    }
+    // prestashop.cart is not available (e.g. voucher removal goes through a raw fetch,
+    // so resp.cart is undefined). Fetch totals from the dedicated endpoint instead.
+    const cartTotalsUrl = getConfiguredOpcUrl('cartTotals');
+    if (!cartTotalsUrl) {
+      return;
+    }
+    fetch(cartTotalsUrl, {credentials: 'same-origin'})
+      .then((r) => r.json())
+      .then((data) => {
+        if (data && data.success && data.totals) {
+          updatePayAmount(data.totals);
+        }
+      })
+      .catch(() => {});
+  });
+});
+}());
diff --git a/views/js/runtime/opc-runtime.js b/views/js/runtime/opc-runtime.js
new file mode 100644
index 0000000..915744c
--- /dev/null
+++ b/views/js/runtime/opc-runtime.js
@@ -0,0 +1,95 @@
+import OPC_EVENTS from '../events';
+import OPC_SELECTORS from '../selectors';
+
+export function isPlainObject(value) {
+  return value !== null && typeof value === 'object' && !Array.isArray(value);
+}
+
+export function normalizeErrorResponse(response, fallbackMessage) {
+  if (isPlainObject(response)) {
+    return response;
+  }
+
+  return {
+    errors: {
+      '': [fallbackMessage],
+    },
+  };
+}
+
+export function getAjaxErrorResponse(jqXHR, fallbackMessage) {
+  return normalizeErrorResponse(jqXHR && jqXHR.responseJSON, fallbackMessage);
+}
+
+export function getOpcRuntimeConfiguration() {
+  if (!window || typeof window.ps_onepagecheckout !== 'object' || !window.ps_onepagecheckout) {
+    return null;
+  }
+
+  return window.ps_onepagecheckout;
+}
+
+export function getConfiguredOpcUrl(urlKey) {
+  const runtimeConfiguration = getOpcRuntimeConfiguration();
+
+  if (runtimeConfiguration && runtimeConfiguration.urls && runtimeConfiguration.urls[urlKey]) {
+    return String(runtimeConfiguration.urls[urlKey]);
+  }
+
+  return '';
+}
+
+export function updateCartSummary(preview, totals) {
+  if (typeof preview !== 'string' || preview === '') {
+    return;
+  }
+
+  const prestashop = window.prestashop || null;
+  const summarySelector = prestashop && prestashop.selectors
+    && prestashop.selectors.checkout
+    && prestashop.selectors.checkout.summarySelector
+    ? String(prestashop.selectors.checkout.summarySelector)
+    : '';
+
+  if (!summarySelector) {
+    return;
+  }
+
+  if (prestashop && typeof prestashop.emit === 'function') {
+    prestashop.emit(OPC_EVENTS.opcCartSummaryBeforeUpdate, {selector: summarySelector});
+  }
+
+  const currentSummary = document.querySelector(summarySelector);
+  if (currentSummary instanceof HTMLElement) {
+    currentSummary.outerHTML = preview;
+  }
+
+  if (prestashop && typeof prestashop.emit === 'function') {
+    prestashop.emit(OPC_EVENTS.opcCartSummaryUpdated, {selector: summarySelector});
+  }
+
+  updatePayAmount(totals);
+}
+
+export function updatePayAmount(totals) {
+  const prestashop = window.prestashop || null;
+
+  const totalValue = totals && typeof totals === 'object'
+    ? (totals.total && totals.total.value) || (totals.total_including_tax && totals.total_including_tax.value) || ''
+    : '';
+  const configuredPayAmountSelector = prestashop && prestashop.selectors
+    && prestashop.selectors.opc
+    && prestashop.selectors.opc.payAmount
+    ? String(prestashop.selectors.opc.payAmount)
+    : '';
+  const payAmountSelector = configuredPayAmountSelector || OPC_SELECTORS.opc.payAmount;
+
+  if (!totalValue || !payAmountSelector) {
+    return;
+  }
+
+  const payAmount = document.querySelector(payAmountSelector);
+  if (payAmount instanceof HTMLElement) {
+    payAmount.textContent = String(totalValue);
+  }
+}
diff --git a/views/js/selectors.js b/views/js/selectors.js
new file mode 100644
index 0000000..08e64fd
--- /dev/null
+++ b/views/js/selectors.js
@@ -0,0 +1,40 @@
+const OPC_SELECTORS = {
+  opc: {
+    checkout: '.one-page-checkout',
+    form: '#opc-form',
+    payButton: '#opc-pay-button',
+    payAmount: '#opc-pay-amount',
+    addressesSection: '.js-opc-addresses-section',
+    deliveryMethods: '#opc-delivery-methods',
+    paymentMethods: '#opc-payment-methods',
+    deliverySection: '#opc-delivery-address',
+    deliveryFields: '#opc-delivery-address-fields',
+    billingSection: '#opc-billing-section',
+    billingFields: '#opc-billing-address-fields',
+    deliveryList: '#opc-delivery-address-content-list',
+    billingList: '#opc-billing-address-content-list',
+    useSameAddress: '[name="use_same_address"]',
+    checkoutFooter: '.one-page-checkout__footer',
+    contactSection: '.js-opc-contact-section',
+    addressRadio: '.js-opc-address-radio',
+    addressItem: '.opc-address-item',
+    addressLabel: '.form-check-label',
+  },
+  templates: {
+    carrierLoader: '#opc-template-loader',
+    carrierError: '#opc-template-carriers-error',
+    paymentLoader: '#opc-template-payment-loader',
+    paymentError: '#opc-template-payment-error',
+  },
+  inputs: {
+    deliveryOption: 'input[name="delivery_option"]',
+    paymentOption: 'input[name="payment-option"]',
+    email: 'input[name="email"]',
+    conditions: '.one-page-checkout input[name^="conditions_to_approve["][required]',
+  },
+  modals: {
+    address: '#opc-address-modal, #modal-delivery, #modal-invoice',
+  },
+};
+
+export default OPC_SELECTORS;
diff --git a/views/public/opc-address-modal.bundle.js b/views/public/opc-address-modal.bundle.js
new file mode 100644
index 0000000..da88340
--- /dev/null
+++ b/views/public/opc-address-modal.bundle.js
@@ -0,0 +1 @@
+(()=>{"use strict";const e={opcCarrierSelected:"opcCarrierSelected",opcCarriersUpdated:"opcCarriersUpdated",opcCarriersFailed:"opcCarriersFailed",opcCarriersLoading:"opcCarriersLoading",opcPaymentMethodsLoading:"opcPaymentMethodsLoading",opcPaymentMethodsUpdated:"opcPaymentMethodsUpdated",opcPaymentMethodsFailed:"opcPaymentMethodsFailed",opcPaymentMethodSelected:"opcPaymentMethodSelected",opcGuestInitSuccess:"opcGuestInitSuccess",opcFinalSubmitStarted:"opcFinalSubmitStarted",opcFormValidated:"opcFormValidated",opcBillingSectionToggled:"opcBillingSectionToggled",opcSubmitFailed:"opcSubmitFailed",opcDeliveryAddressUpdated:"opcDeliveryAddressUpdated",opcBillingAddressUpdated:"opcBillingAddressUpdated",opcDeliveryAddressSelected:"opcDeliveryAddressSelected",opcBillingAddressSelected:"opcBillingAddressSelected",opcCartSummaryBeforeUpdate:"opcCartSummaryBeforeUpdate",opcCartSummaryUpdated:"opcCartSummaryUpdated",updatedOpcAddressForm:"updatedOpcAddressForm",opcCarriersRetry:"opcCarriersRetry",opcPaymentMethodsRetry:"opcPaymentMethodsRetry"};const t={opc:{checkout:".one-page-checkout",form:"#opc-form",payButton:"#opc-pay-button",payAmount:"#opc-pay-amount",addressesSection:".js-opc-addresses-section",deliveryMethods:"#opc-delivery-methods",paymentMethods:"#opc-payment-methods",deliverySection:"#opc-delivery-address",deliveryFields:"#opc-delivery-address-fields",billingSection:"#opc-billing-section",billingFields:"#opc-billing-address-fields",deliveryList:"#opc-delivery-address-content-list",billingList:"#opc-billing-address-content-list",useSameAddress:'[name="use_same_address"]',checkoutFooter:".one-page-checkout__footer",contactSection:".js-opc-contact-section",addressRadio:".js-opc-address-radio",addressItem:".opc-address-item",addressLabel:".form-check-label"},templates:{carrierLoader:"#opc-template-loader",carrierError:"#opc-template-carriers-error",paymentLoader:"#opc-template-payment-loader",paymentError:"#opc-template-payment-error"},inputs:{deliveryOption:'input[name="delivery_option"]',paymentOption:'input[name="payment-option"]',email:'input[name="email"]',conditions:'.one-page-checkout 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s=String(o.attr("data-text")||o.text()),c=String(o.attr("data-loading-text")||s),l=function(e){var t=[];return e.find("input, select, textarea").each(function(e,n){var o=r(n),i=String(o.attr("name")||"");""===i||o.prop("disabled")||(!o.is(":checkbox")&&!o.is(":radio")||o.is(":checked"))&&t.push({name:i,value:String(o.val()||"")})}),t.push({name:"use_same_address",value:G(r(b).first())?"1":"0"}),r.param(t)}(d),p=new URLSearchParams(l),u=String(p.get("address_type")||(d.is("#modal-invoice")?"invoice":"delivery"));o.prop("disabled",!0).text(c),r.post(t,l).done(function(e){if(!e||!1===e.success)return Z(d,e&&e.errors?e.errors:{}),void i.emit("handleError",{eventType:"opcSaveAddress",resp:e||{}});z(d),d.attr(F,"1"),oe(d),se({refreshDeliverySelection:"delivery"===u,refreshBillingSelection:"invoice"===u}),ne(e.message||"")}).fail(function(e){i.emit("handleError",{eventType:"opcSaveAddress",resp:e.responseJSON||{}})}).always(function(){o.prop("disabled",!1).text(s)})}else i.emit("handleError",{eventType:"opcSaveAddress",resp:{errors:{"":["Missing OPC save address URL."]}}})}),r(document).on("click",".js-delete-address",function(e){e.preventDefault();var t=n(h),o=r(e.currentTarget);t&&o.length?Y().then(function(e){e&&(o.prop("disabled",!0),r.post(t,{id_address:String(o.attr("data-id-address")||"")}).done(function(e){if(!e||!1===e.success)return i.emit("handleError",{eventType:"opcDeleteAddress",resp:e||{}}),void o.prop("disabled",!1);se({resetInlineAddressState:!0}),ne(e.message||"")}).fail(function(e){i.emit("handleError",{eventType:"opcDeleteAddress",resp:e.responseJSON||{}}),o.prop("disabled",!1)}))}):i.emit("handleError",{eventType:"opcDeleteAddress",resp:{errors:{"":["Missing OPC delete address URL."]}}})}),r(function(){P(),r(a).each(function(e,t){return K(r(t))}),ae(),$()}),i.on(e.updatedOpcAddressForm,function(){P(),r(a).each(function(e,t){return K(r(t))}),$()})}function B(e){return String(e.prop("type")||"").toLowerCase()}function I(e,t){return!function(e){return!e||L.has(e)}(e)&&!T.has(B(t))}function U(e){var t=Object.create(null);return e.find("input, select, textarea").each(function(e,n){var o=r(n),i=String(o.prop("name")||"");I(i,o)&&function(e,t,r){var n=B(r);if("checkbox"===n)return Array.isArray(e[t])||(e[t]=[]),void(r.is(":checked")&&e[t].push(String(r.val())));"radio"!==n?e[t]=r.val():r.is(":checked")&&(e[t]=String(r.val()))}(t,i,o)}),t}function O(e,t){e.find("input, select, textarea").each(function(e,n){var o=r(n),i=String(o.prop("name")||"");I(i,o)&&function(e,t){var r=B(e);if(void 0!==t)if("checkbox"!==r)"radio"!==r?e.val(t):e.prop("checked",String(e.val())===String(t));else{var n=Array.isArray(t)?t:[];e.prop("checked",n.includes(String(e.val())))}}(o,t[i])})}function R(e,t){e.find("input, select, textarea").each(function(e,n){var o=r(n);o.is('[type="hidden"]')||function(e){return e.is(':button, [type="button"], [type="submit"], [type="reset"], [type="image"], [type="file"]')}(o)||o.prop("disabled",t)})}function P(){r(a).each(function(e,t){var n=r(t);n.hasClass("show")||R(n,!0)})}function $(){var e=document.querySelector(t.opc.checkout);e&&e.dispatchEvent(new Event("change",{bubbles:!0}))}function H(e,t){var r=e.find('[name="'.concat(t,'"]')).first();return r.length?r:e.find('[name$="'.concat(t,'"]')).first()}function q(e,t,r){var n=e.find(r).first();return n.length?n:e.find(t).first()}function J(e,t,r,n){var o=q(e,t,r);if(!o.length)return"";var i=o.find('[name="'.concat(n,'"]')).first();return i.length?String(i.val()||""):""}function N(e,t,r,n,o){if(null!=o&&""!==String(o)){var i=q(e,t,r);if(i.length){var d=i.find('[name="'.concat(n,'"]')).first();d.length&&d.val(String(o))}}}function V(e){return e.find(t.opc.useSameAddress).first()}function G(e){var t=V(e);return!!t.length&&t.is(":checked")}function z(e){e.find(".".concat(E)).remove(),e.find(".".concat(x)).remove(),e.find(".is-invalid").removeClass("is-invalid")}function Q(e){return!(e instanceof HTMLInputElement||e instanceof HTMLSelectElement||e instanceof HTMLTextAreaElement)||(!(!e.disabled&&function(e){if(!(e instanceof HTMLElement))return!1;var t=window.getComputedStyle(e);return"none"!==t.display&&"hidden"!==t.visibility&&e.getClientRects().length>0}(e))||e.checkValidity())}function K(e){var t=e.find(s);if(t.length)if(e.get(0)instanceof HTMLElement&&e.hasClass("show")){var r=e.find("input, select, textarea").toArray().every(function(e){return Q(e)});t.prop("disabled",!r)}else t.prop("disabled",!0)}function W(e,t,n){var o=function(e){return{$wrapper:e.find(".state-field-wrapper, #state-field-wrapper").first(),$select:e.find('[name="id_state"], [name$="id_state"]').first(),$row:e.find(".address-country-row, #address-country-row").first()}}(e),i=o.$wrapper,d=o.$select,a=o.$row;if(i.length&&d.length){var s=t&&Array.isArray(t.states)?t.states:[];if(!(Boolean(t&&t.hasStates)||s.length>0))return i.hide(),d.prop("required",!1).val(""),void(a.length&&a.removeClass("form-fields-row--3").addClass("form-fields-row--2"));var c=String(d.attr("data-select-placeholder")||"");d.empty(),d.append(r("<option>",{value:"",text:c})),s.forEach(function(e){var t=String(e.id_state||"");d.append(r("<option>",{value:t,text:String(e.name||""),selected:""!==n&&t===n}))}),i.show(),d.prop("required",!0),a.length&&a.removeClass("form-fields-row--2").addClass("form-fields-row--3")}}function X(e,t,o){var d=n(g);return d&&""!==t?r.get(d,{id_country:t}).done(function(t){W(e,t||{},o),K(e)}).fail(function(t){W(e,{hasStates:!1,states:[]},""),K(e),i.emit("handleError",{eventType:"opcAddressStates",resp:t.responseJSON||{errors:{"":["Unable to load states."]}}})}):(W(e,{hasStates:!1,states:[]},""),r.Deferred().resolve().promise())}function Y(){var e=r.Deferred(),t=r("#".concat("opc-delete-address-confirm-modal")),n=!1;if(!t.length)return e.resolve(!1),e.promise();return t.on("click.opcDeleteConfirm",".js-opc-delete-address-confirm",function(){n=!0,oe(t)}),t.on("hidden.bs.modal.opcDeleteConfirm",function(){t.off(".opcDeleteConfirm"),e.resolve(n)}),function(e){if(!e.length)return;if(window.bootstrap&&"function"==typeof window.bootstrap.Modal)return void window.bootstrap.Modal.getOrCreateInstance(e.get(0)).show();"function"==typeof e.modal&&e.modal("show")}(t),e.promise()}function Z(e,t){z(e),t&&"object"===d(t)&&Object.entries(t).forEach(function(t){var n,i,d=o(t,2),a=d[0],s=d[1],c=Array.isArray(s)?s.filter(Boolean):[];0!==c.length&&(""!==a?(n=H(e,a),i=c[0],n.length&&i&&(n.addClass("is-invalid"),(n.closest(".form-group").length?n.closest(".form-group"):n.parent()).append(r("<div>",{class:"invalid-feedback d-block ".concat(E),text:i})))):e.find(".modal-body").first().prepend(r("<div>",{class:"alert alert-danger ".concat(x),text:c.join(" ")})))})}function ee(e){return"id_address_delivery"===e?t.opc.deliveryList:"id_address_invoice"===e?t.opc.billingList:""}function te(e){e.removeAttr(j),e.removeAttr(D),e.removeAttr(F)}function re(e){var t=ee(e),n=function(e){return"id_address_delivery"===e?r("#modal-delivery"):"id_address_invoice"===e?r("#modal-invoice"):r()}(e);if(t&&n.length){var o=ce(t,e);te(n),o.idAddress&&(n.attr(j,o.idAddress),n.attr(D,e))}}function ne(e){var t=String(e||"").trim();if(""!==t)if(window.Theme&&window.Theme.components&&"function"==typeof window.Theme.components.useToast){var n=window.Theme.components.useToast(t,{type:"success"});n&&"function"==typeof n.show&&n.show()}else r("body").append(r("<div>",{class:"alert alert-success",text:t}))}function oe(e){if(e.length){if(window.bootstrap&&"function"==typeof window.bootstrap.Modal){var t=window.bootstrap.Modal.getInstance(e.get(0));if(t)return void t.hide()}"function"==typeof e.modal&&e.modal("hide")}}function ie(){var t=arguments.length>0&&void 0!==arguments[0]?arguments[0]:{},o=n(S),d=r(b).first(),a=Boolean(t.resetInlineAddressState);if(!o||!d.length)return r.Deferred().resolve().promise();var s={use_same_address:G(d)?"1":"0"};a||(s.id_address_delivery=J(d,_,w,"id_address_delivery"),s.id_address_invoice=J(d,A,C,"id_address_invoice"),s.id_country=J(d,_,w,"id_country"),s.invoice_id_country=J(d,A,C,"invoice_id_country"));var c="0"!==s.use_same_address,l=U(d);return r.post(o,s).done(function(t){t&&"string"==typeof t.addresses_section&&(d.html(t.addresses_section),O(d,l),function(e,t){V(e).prop("checked",t)}(d,c),function(e,t){var n=e.find(A).first();n.length&&(n.toggle(!t),n.find("input, select, textarea").each(function(e,n){var o=r(n);t?o.prop("disabled")||(o.attr(k,"1"),o.prop("disabled",!0)):"1"===o.attr(k)&&(o.prop("disabled",!1),o.removeAttr(k))}))}(d,c),a||(N(d,_,w,"id_country",s.id_country),N(d,A,C,"invoice_id_country",s.invoice_id_country)),ae(),i.emit(e.updatedOpcAddressForm,{target:d,resp:t}),i.emit(e.opcDeliveryAddressUpdated,{resp:t}),i.emit(e.opcBillingAddressUpdated,{resp:t}))})}function de(e){e.length&&e.find(t.opc.addressItem).each(function(e,n){var o=r(n),i=o.find(t.opc.addressRadio).first().is(":checked");o.toggleClass("border-primary selected z-1",i),o.find(t.opc.addressLabel).first().toggleClass("fw-semibold",i)})}function ae(){de(r(t.opc.deliveryList)),de(r(t.opc.billingList))}function se(){var d=arguments.length>0&&void 0!==arguments[0]?arguments[0]:{},a=n(v);return a?([[t.opc.deliveryList,"#opc-delivery-address-loader"],[t.opc.billingList,"#opc-billing-address-loader"]].forEach(function(e){var t=o(e,2),n=t[0],i=t[1],d=r(n),a=r(i).html();d.length&&a&&d.html(a)}),r.post(a).then(function(n){return n&&!1!==n.success&&void 0!==n.address_count?(parseInt(n.address_count,10)||0)<=0?ie(d):(function(n){var o=arguments.length>1&&void 0!==arguments[1]?arguments[1]:{},i=ce(t.opc.deliveryList,"id_address_delivery"),d=ce(t.opc.billingList,"id_address_invoice"),a=parseInt(n.address_count,10)||0,s=r(t.opc.deliveryList),c=r(w),l=r(t.opc.billingList),p=r(C);s.length&&"string"==typeof n.delivery_html&&s.html(n.delivery_html),l.length&&"string"==typeof n.billing_html&&l.html(n.billing_html),s.toggleClass("d-none",a<=0),c.toggleClass("d-none",a>0),l.toggleClass("d-none",a<=1),p.toggleClass("d-none",a>1),ae(),le(e.opcDeliveryAddressSelected,i,ce(t.opc.deliveryList,"id_address_delivery"),Boolean(o.refreshDeliverySelection)),le(e.opcBillingAddressSelected,d,ce(t.opc.billingList,"id_address_invoice"),Boolean(o.refreshBillingSelection))}(n,d),n):ie(d)}).fail(function(e){return i.emit("handleError",{eventType:"opcAddressesList",resp:e.responseJSON||{}}),ie(d)})):ie(d)}function ce(e,n){var o=r(e).find("".concat(t.opc.addressRadio,'[name="').concat(n,'"]:checked')).first(),i=String(o.val()||"");if(!o.length||""===i||"new_address"===i)return{idAddress:"",target:null};var d=o.closest(t.opc.addressItem);return{idAddress:i,target:d.length?d.get(0):o.get(0)}}function le(e,t,r){var n=arguments.length>3&&void 0!==arguments[3]&&arguments[3];r.idAddress&&(n||t.idAddress!==r.idAddress)&&i.emit(e,r)}}()})();
\ No newline at end of file
diff --git a/views/public/opc-address.bundle.js b/views/public/opc-address.bundle.js
index c7bfb92..ee1c9ee 100644
--- a/views/public/opc-address.bundle.js
+++ b/views/public/opc-address.bundle.js
@@ -1,2 +1,2 @@
 /*! For license information please see opc-address.bundle.js.LICENSE.txt */
-(()=>{function e(r){return e="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(e){return typeof e}:function(e){return e&&"function"==typeof Symbol&&e.constructor===Symbol&&e!==Symbol.prototype?"symbol":typeof e},e(r)}!function(){var r=window.$||window.jQuery,n=window.prestashop||{},t='[name="use_same_address"]',o="data-opc-disabled-by-same-address",s=new Set(["id_country","invoice_id_country","id_state","invoice_id_state","use_same_address"]);function a(e){return String(e.prop("type")||"").toLowerCase()}var d=new Set(["hidden","file","submit","button","image","reset"]);function i(e,r){return!function(e){return!e||s.has(e)}(e)&&!d.has(a(r))}function c(e){var n=Object.create(null);return r(e).each(function(){var e=r(this),t=e.prop("name");i(t,e)&&function(e,r,n){var t=a(n);if("checkbox"===t)return Array.isArray(e[r])||(e[r]=[]),void(n.is(":checked")&&e[r].push(String(n.val())));"radio"!==t?e[r]=n.val():n.is(":checked")&&(e[r]=String(n.val()))}(n,t,e)}),n}function u(e,n){r(e).each(function(){var e=r(this),t=e.prop("name");i(t,e)&&function(e,r){var n=a(e);if(void 0!==r)if("checkbox"!==n)"radio"!==n?e.val(r):e.prop("checked",String(e.val())===String(r));else{var t=Array.isArray(r)?r:[];e.prop("checked",t.includes(String(e.val())))}}(e,n[t])})}function p(r){var n=window&&"object"===e(window.ps_onepagecheckout)&&window.ps_onepagecheckout?window.ps_onepagecheckout:null;return n&&n.urls&&n.urls[r]?String(n.urls[r]):""}function f(e,n){var t=e.find("#opc-billing-section");t.length&&(t.toggle(!n),t.find("input, select, textarea").each(function(e,t){var s=r(t);n?s.prop("disabled")||(s.attr(o,"1"),s.prop("disabled",!0)):"1"===s.attr(o)&&(s.prop("disabled",!1),s.removeAttr(o))}))}function l(e){return e.find(t).is(":checked")}r(function(){var e={country:".js-opc-address-form .js-country",address:".js-opc-address-form"};!function(e){r("body").on("change",e.country,function(t){var o=r(t.target).closest(e.address);if(o.length){var s={id_country:o.find('[name="id_country"]').val(),invoice_id_country:o.find('[name="invoice_id_country"]').val(),use_same_address:o.find('[name="use_same_address"]').is(":checked")?"1":"0"},a="".concat(e.address," input, ").concat(e.address," select, ").concat(e.address," textarea"),d=p("addressForm");""!==d?r.post(d,s).then(function(t){if(t&&"string"==typeof t.address_form){var d=c(a);o.html(t.address_form),u(a,d);var i="0"!==s.use_same_address;o.find('[name="use_same_address"]').prop("checked",i),f(o,i),n.emit("updatedOpcAddressForm",{target:r(e.address),resp:t})}else n.emit("handleError",{eventType:"updateOpcAddressForm",resp:t})}).fail(function(e){n.emit("handleError",{eventType:"updateOpcAddressForm",resp:e})}):n.emit("handleError",{eventType:"updateOpcAddressForm",resp:{errors:{"":["Missing OPC address form URL."]}}})}})}(e),function(e){r("body").on("change","".concat(e.address," ").concat(t),function(n){var t=r(n.target).closest(e.address);t.length&&f(t,l(t))})}(e),function(e){var n=r(e.address).first();n.length&&f(n,l(n))}(e)})}()})();
\ No newline at end of file
+(()=>{"use strict";const e={opcCarrierSelected:"opcCarrierSelected",opcCarriersUpdated:"opcCarriersUpdated",opcCarriersFailed:"opcCarriersFailed",opcCarriersLoading:"opcCarriersLoading",opcPaymentMethodsLoading:"opcPaymentMethodsLoading",opcPaymentMethodsUpdated:"opcPaymentMethodsUpdated",opcPaymentMethodsFailed:"opcPaymentMethodsFailed",opcPaymentMethodSelected:"opcPaymentMethodSelected",opcGuestInitSuccess:"opcGuestInitSuccess",opcFinalSubmitStarted:"opcFinalSubmitStarted",opcFormValidated:"opcFormValidated",opcBillingSectionToggled:"opcBillingSectionToggled",opcSubmitFailed:"opcSubmitFailed",opcDeliveryAddressUpdated:"opcDeliveryAddressUpdated",opcBillingAddressUpdated:"opcBillingAddressUpdated",opcDeliveryAddressSelected:"opcDeliveryAddressSelected",opcBillingAddressSelected:"opcBillingAddressSelected",opcCartSummaryBeforeUpdate:"opcCartSummaryBeforeUpdate",opcCartSummaryUpdated:"opcCartSummaryUpdated",updatedOpcAddressForm:"updatedOpcAddressForm",opcCarriersRetry:"opcCarriersRetry",opcPaymentMethodsRetry:"opcPaymentMethodsRetry"};const t={opc:{checkout:".one-page-checkout",form:"#opc-form",payButton:"#opc-pay-button",payAmount:"#opc-pay-amount",addressesSection:".js-opc-addresses-section",deliveryMethods:"#opc-delivery-methods",paymentMethods:"#opc-payment-methods",deliverySection:"#opc-delivery-address",deliveryFields:"#opc-delivery-address-fields",billingSection:"#opc-billing-section",billingFields:"#opc-billing-address-fields",deliveryList:"#opc-delivery-address-content-list",billingList:"#opc-billing-address-content-list",useSameAddress:'[name="use_same_address"]',checkoutFooter:".one-page-checkout__footer",contactSection:".js-opc-contact-section",addressRadio:".js-opc-address-radio",addressItem:".opc-address-item",addressLabel:".form-check-label"},templates:{carrierLoader:"#opc-template-loader",carrierError:"#opc-template-carriers-error",paymentLoader:"#opc-template-payment-loader",paymentError:"#opc-template-payment-error"},inputs:{deliveryOption:'input[name="delivery_option"]',paymentOption:'input[name="payment-option"]',email:'input[name="email"]',conditions:'.one-page-checkout input[name^="conditions_to_approve["][required]'},modals:{address:"#opc-address-modal, #modal-delivery, #modal-invoice"}};function r(e){return r="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(e){return typeof e}:function(e){return e&&"function"==typeof Symbol&&e.constructor===Symbol&&e!==Symbol.prototype?"symbol":typeof e},r(e)}function o(e){var t=window&&"object"===r(window.ps_onepagecheckout)&&window.ps_onepagecheckout?window.ps_onepagecheckout:null;return t&&t.urls&&t.urls[e]?String(t.urls[e]):""}!function(){var r=window.$||window.jQuery,i=window.prestashop||{},n=t.opc.addressesSection,d=t.opc.billingSection,a=t.opc.deliverySection,c=t.opc.deliveryFields,s=t.opc.billingFields,p=t.modals.address,l='[name="use_same_address"]',u="data-opc-disabled-by-same-address",m=new Set(["id_country","invoice_id_country","id_state","invoice_id_state","use_same_address"]);function y(e){return String(e.prop("type")||"").toLowerCase()}var f=new Set(["hidden","file","submit","button","image","reset"]);function v(e,t){return!function(e){return!e||m.has(e)}(e)&&(!(t.closest(p).length>0)&&!f.has(y(t)))}function g(e){var t=Object.create(null);return r(e).each(function(){var e=r(this),o=e.prop("name");v(o,e)&&function(e,t,r){var o=y(r);if("checkbox"===o)return Array.isArray(e[t])||(e[t]=[]),void(r.is(":checked")&&e[t].push(String(r.val())));"radio"!==o?e[t]=r.val():r.is(":checked")&&(e[t]=String(r.val()))}(t,o,e)}),t}function h(e,t){r(e).each(function(){var e=r(this),o=e.prop("name");v(o,e)&&function(e,t){var r=y(e);if(void 0!==t)if("checkbox"!==r)"radio"!==r?e.val(t):e.prop("checked",String(e.val())===String(t));else{var o=Array.isArray(t)?t:[];e.prop("checked",o.includes(String(e.val())))}}(e,t[o])})}function _(e,t){var o=e.find(d);o.length&&(o.toggle(!t),o.find("input, select, textarea").each(function(e,o){var i=r(o);t?i.prop("disabled")||(i.attr(u,"1"),i.prop("disabled",!0)):"1"===i.attr(u)&&(i.prop("disabled",!1),i.removeAttr(u))}))}function S(e){return e.find(l).first().is(":checked")}function b(e,t,r){var o=e.find(r).first();return o.length?o:e.find(t).first()}function F(e,t,r,o){var i=b(e,t,r);if(!i.length)return"";var n=i.find('[name="'.concat(o,'"]')).first();return n.length?String(n.val()||""):""}function A(e,t,r,o,i){if(null!=i&&""!==String(i)){var n=b(e,t,r);if(n.length){var d=n.find('[name="'.concat(o,'"]')).first();d.length&&d.val(String(i))}}}function k(e){if(""!==F(e,d,s,"id_address_invoice"))return!0;var t=b(e,d,s);if(!t.length)return!1;var o=!1;return t.find("input, select, textarea").each(function(){var e=r(this);if(v(String(e.prop("name")||""),e)&&function(e){var t=y(e);return"checkbox"===t||"radio"===t?e.is(":checked"):""!==String(e.val()||"").trim()}(e))return o=!0,!1}),o}function w(e){r("body").on("change","".concat(e.address," ").concat(l),function(t){var o=r(t.target).closest(e.address);if(o.length){var i=S(o);_(o,i),i||k(o)||function(e){var t=F(e,a,c,"id_country"),r=F(e,a,c,"id_state"),o=b(e,d,s).find('[name="invoice_id_country"]').first(),i=o.length?String(o.val()||""):"";A(e,d,s,"invoice_id_country",t),o.length&&""!==t&&i!==t?o.val(t).trigger("change"):A(e,d,s,"invoice_id_state",r)}(o)}})}function C(t,n){if(t.length&&!(t.closest(p).length>0||r(p).filter(".show").length>0)){var u=t.closest(n.address);if(u.length){var m=String(t.attr("name")||""),y="id_country"===m?String(t.val()||""):F(u,a,c,"id_country"),f="invoice_id_country"===m?String(t.val()||""):F(u,d,s,"invoice_id_country"),v={id_address_delivery:F(u,a,c,"id_address_delivery"),id_address_invoice:F(u,d,s,"id_address_invoice"),id_country:y,invoice_id_country:f,use_same_address:S(u)?"1":"0"},b="".concat(n.address," input, ").concat(n.address," select, ").concat(n.address," textarea"),A=o("addressForm");""!==A?r.post(A,v).then(function(t){if(t&&"string"==typeof t.addresses_section){var r=g(b);u.html(t.addresses_section),h(b,r);var o="0"!==v.use_same_address;!function(e,t){e.find(l).first().prop("checked",t)}(u,o),_(u,o),i.emit(e.updatedOpcAddressForm,{target:u,resp:t}),i.emit(e.opcDeliveryAddressUpdated,{target:u,resp:t}),i.emit(e.opcBillingAddressUpdated,{target:u,resp:t})}else i.emit("handleError",{eventType:"updateOpcAddressForm",resp:t})}).fail(function(e){i.emit("handleError",{eventType:"updateOpcAddressForm",resp:e})}):i.emit("handleError",{eventType:"updateOpcAddressForm",resp:{errors:{"":["Missing OPC address form URL."]}}})}}}r(function(){var e={address:n};!function(e){r("body").on("change","".concat(t.opc.deliveryFields,' select[name="id_country"], ').concat(t.opc.billingFields,' select[name="invoice_id_country"]'),function(t){C(r(t.target),e)})}(e),w(e),function(e){var t=r(e.address).first();t.length&&_(t,S(t))}(e)})}()})();
\ No newline at end of file
diff --git a/views/public/opc-carrier-list.bundle.js b/views/public/opc-carrier-list.bundle.js
new file mode 100644
index 0000000..f423ff5
--- /dev/null
+++ b/views/public/opc-carrier-list.bundle.js
@@ -0,0 +1 @@
+(()=>{"use strict";const e={opcCarrierSelected:"opcCarrierSelected",opcCarriersUpdated:"opcCarriersUpdated",opcCarriersFailed:"opcCarriersFailed",opcCarriersLoading:"opcCarriersLoading",opcPaymentMethodsLoading:"opcPaymentMethodsLoading",opcPaymentMethodsUpdated:"opcPaymentMethodsUpdated",opcPaymentMethodsFailed:"opcPaymentMethodsFailed",opcPaymentMethodSelected:"opcPaymentMethodSelected",opcGuestInitSuccess:"opcGuestInitSuccess",opcFinalSubmitStarted:"opcFinalSubmitStarted",opcFormValidated:"opcFormValidated",opcBillingSectionToggled:"opcBillingSectionToggled",opcSubmitFailed:"opcSubmitFailed",opcDeliveryAddressUpdated:"opcDeliveryAddressUpdated",opcBillingAddressUpdated:"opcBillingAddressUpdated",opcDeliveryAddressSelected:"opcDeliveryAddressSelected",opcBillingAddressSelected:"opcBillingAddressSelected",opcCartSummaryBeforeUpdate:"opcCartSummaryBeforeUpdate",opcCartSummaryUpdated:"opcCartSummaryUpdated",updatedOpcAddressForm:"updatedOpcAddressForm",opcCarriersRetry:"opcCarriersRetry",opcPaymentMethodsRetry:"opcPaymentMethodsRetry"};const r={opc:{checkout:".one-page-checkout",form:"#opc-form",payButton:"#opc-pay-button",payAmount:"#opc-pay-amount",addressesSection:".js-opc-addresses-section",deliveryMethods:"#opc-delivery-methods",paymentMethods:"#opc-payment-methods",deliverySection:"#opc-delivery-address",deliveryFields:"#opc-delivery-address-fields",billingSection:"#opc-billing-section",billingFields:"#opc-billing-address-fields",deliveryList:"#opc-delivery-address-content-list",billingList:"#opc-billing-address-content-list",useSameAddress:'[name="use_same_address"]',checkoutFooter:".one-page-checkout__footer",contactSection:".js-opc-contact-section",addressRadio:".js-opc-address-radio",addressItem:".opc-address-item",addressLabel:".form-check-label"},templates:{carrierLoader:"#opc-template-loader",carrierError:"#opc-template-carriers-error",paymentLoader:"#opc-template-payment-loader",paymentError:"#opc-template-payment-error"},inputs:{deliveryOption:'input[name="delivery_option"]',paymentOption:'input[name="payment-option"]',email:'input[name="email"]',conditions:'.one-page-checkout input[name^="conditions_to_approve["][required]'},modals:{address:"#opc-address-modal, #modal-delivery, #modal-invoice"}};function t(e){return t="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(e){return typeof e}:function(e){return e&&"function"==typeof Symbol&&e.constructor===Symbol&&e!==Symbol.prototype?"symbol":typeof e},t(e)}function o(e,r){return null===(o=e)||"object"!==t(o)||Array.isArray(o)?{errors:{"":[r]}}:e;var o}function a(e){var r=window&&"object"===t(window.ps_onepagecheckout)&&window.ps_onepagecheckout?window.ps_onepagecheckout:null;return r&&r.urls&&r.urls[e]?String(r.urls[e]):""}function d(o,a){if("string"==typeof o&&""!==o){var d=window.prestashop||null,i=d&&d.selectors&&d.selectors.checkout&&d.selectors.checkout.summarySelector?String(d.selectors.checkout.summarySelector):"";if(i){d&&"function"==typeof d.emit&&d.emit(e.opcCartSummaryBeforeUpdate,{selector:i});var c=document.querySelector(i);c instanceof HTMLElement&&(c.outerHTML=o),d&&"function"==typeof d.emit&&d.emit(e.opcCartSummaryUpdated,{selector:i}),function(e){var o=window.prestashop||null,a=e&&"object"===t(e)&&(e.total&&e.total.value||e.total_including_tax&&e.total_including_tax.value)||"",d=o&&o.selectors&&o.selectors.opc&&o.selectors.opc.payAmount?String(o.selectors.opc.payAmount):"",i=d||r.opc.payAmount;if(!a||!i)return;var c=document.querySelector(i);c instanceof HTMLElement&&(c.textContent=String(a))}(a)}}}!function(){var t=window.$||window.jQuery,i=window.prestashop||{};if(t){var c=r.opc.deliveryMethods,n=r.opc.checkout,s=e.opcCarriersFailed,l=null;t(function(){y()&&f()}),t(document).on("click",'[data-opc-action="retry-carriers"]',function(e){e.preventDefault(),f()}),i.on(e.opcCarriersRetry,f),i.on(e.opcDeliveryAddressUpdated,function(){var e=document.querySelector(c),r=v();if(r)return l=r,e&&e.setAttribute("data-id-address",r),void f();l=null,e&&e.removeAttribute("data-id-address"),f()}),i.on(e.opcDeliveryAddressSelected,function(e){var r=e.idAddress;l=String(r||""),f()});var p=document.querySelector(c),u=v();p&&u&&(l=u)}function m(e){var r=document.querySelector("#".concat(e));return r?r.innerHTML:""}function y(){return document.querySelector(n)}function v(){var e=document.querySelector("".concat(r.opc.deliveryList," ").concat(r.opc.addressRadio,'[name="id_address_delivery"]:checked')),t=e?String(e.getAttribute("value")||""):"";return t&&"new_address"!==t?t:""}function S(e,r){var t=e.querySelector('[name="'.concat(r,'"]')),o=e.querySelector('[name="delivery_'.concat(r,'"]'));return(t&&t.value||o&&o.value||"").trim()}function f(){var n=function(e){var r=y();if(!r||!e)return"";if(l){var t=new URL(e,window.location.origin);return t.searchParams.set("id_address_delivery",l),t.toString()}document.querySelector(c);var o=S(r,"id_country");if(!o)return"";var a=new URL(e,window.location.origin),d=v();a.searchParams.set("id_country",o),d&&a.searchParams.set("id_address_delivery",d);var i=S(r,"postcode"),n=S(r,"id_state"),s=S(r,"city");return i&&a.searchParams.set("postcode",i),n&&a.searchParams.set("id_state",n),s&&a.searchParams.set("city",s),a.toString()}(a("carriers")),p=t(c);n&&p.length&&(p.html(m(r.templates.carrierLoader.replace("#",""))),i.emit(e.opcCarriersLoading,{}),t.get(n).done(function(t){if(!t||!1===t.success){var a=o(t,"Unable to load delivery methods.");return p.html(m(r.templates.carrierError.replace("#",""))),i.emit(s,{resp:a}),void i.emit("handleError",{eventType:"opcCarriers",resp:a})}p.html(t.carriers_html||""),void 0!==t.id_address_delivery&&(t.id_address_delivery?p.attr("data-id-address",String(t.id_address_delivery)):p.removeAttr("data-id-address")),t.preview&&d(t.preview,t.totals),i.emit(e.opcCarriersUpdated,t);var c=p.find("".concat(r.inputs.deliveryOption,":checked")).get(0);c?(p.attr("data-confirmed-delivery-option",String(c.value||"")),i.emit(e.opcCarrierSelected,{carrierId:c.value,resp:t})):p.removeAttr("data-confirmed-delivery-option")}).fail(function(e){var t=function(e,r){return o(e&&e.responseJSON,r)}(e,"Unable to load delivery methods.");p.html(m(r.templates.carrierError.replace("#",""))),i.emit(s,{resp:t}),i.emit("handleError",{eventType:"opcCarriers",resp:t})}))}}()})();
\ No newline at end of file
diff --git a/views/public/opc-carrier-select.bundle.js b/views/public/opc-carrier-select.bundle.js
new file mode 100644
index 0000000..626d297
--- /dev/null
+++ b/views/public/opc-carrier-select.bundle.js
@@ -0,0 +1 @@
+(()=>{"use strict";const e={opcCarrierSelected:"opcCarrierSelected",opcCarriersUpdated:"opcCarriersUpdated",opcCarriersFailed:"opcCarriersFailed",opcCarriersLoading:"opcCarriersLoading",opcPaymentMethodsLoading:"opcPaymentMethodsLoading",opcPaymentMethodsUpdated:"opcPaymentMethodsUpdated",opcPaymentMethodsFailed:"opcPaymentMethodsFailed",opcPaymentMethodSelected:"opcPaymentMethodSelected",opcGuestInitSuccess:"opcGuestInitSuccess",opcFinalSubmitStarted:"opcFinalSubmitStarted",opcFormValidated:"opcFormValidated",opcBillingSectionToggled:"opcBillingSectionToggled",opcSubmitFailed:"opcSubmitFailed",opcDeliveryAddressUpdated:"opcDeliveryAddressUpdated",opcBillingAddressUpdated:"opcBillingAddressUpdated",opcDeliveryAddressSelected:"opcDeliveryAddressSelected",opcBillingAddressSelected:"opcBillingAddressSelected",opcCartSummaryBeforeUpdate:"opcCartSummaryBeforeUpdate",opcCartSummaryUpdated:"opcCartSummaryUpdated",updatedOpcAddressForm:"updatedOpcAddressForm",opcCarriersRetry:"opcCarriersRetry",opcPaymentMethodsRetry:"opcPaymentMethodsRetry"};const t={opc:{checkout:".one-page-checkout",form:"#opc-form",payButton:"#opc-pay-button",payAmount:"#opc-pay-amount",addressesSection:".js-opc-addresses-section",deliveryMethods:"#opc-delivery-methods",paymentMethods:"#opc-payment-methods",deliverySection:"#opc-delivery-address",deliveryFields:"#opc-delivery-address-fields",billingSection:"#opc-billing-section",billingFields:"#opc-billing-address-fields",deliveryList:"#opc-delivery-address-content-list",billingList:"#opc-billing-address-content-list",useSameAddress:'[name="use_same_address"]',checkoutFooter:".one-page-checkout__footer",contactSection:".js-opc-contact-section",addressRadio:".js-opc-address-radio",addressItem:".opc-address-item",addressLabel:".form-check-label"},templates:{carrierLoader:"#opc-template-loader",carrierError:"#opc-template-carriers-error",paymentLoader:"#opc-template-payment-loader",paymentError:"#opc-template-payment-error"},inputs:{deliveryOption:'input[name="delivery_option"]',paymentOption:'input[name="payment-option"]',email:'input[name="email"]',conditions:'.one-page-checkout input[name^="conditions_to_approve["][required]'},modals:{address:"#opc-address-modal, #modal-delivery, #modal-invoice"}};function r(e){return r="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(e){return typeof e}:function(e){return e&&"function"==typeof Symbol&&e.constructor===Symbol&&e!==Symbol.prototype?"symbol":typeof e},r(e)}function o(e,t){return null===(o=e)||"object"!==r(o)||Array.isArray(o)?{errors:{"":[t]}}:e;var o}function n(e,t){return o(e&&e.responseJSON,t)}function c(e){var t=window&&"object"===r(window.ps_onepagecheckout)&&window.ps_onepagecheckout?window.ps_onepagecheckout:null;return t&&t.urls&&t.urls[e]?String(t.urls[e]):""}function i(o,n){if("string"==typeof o&&""!==o){var c=window.prestashop||null,i=c&&c.selectors&&c.selectors.checkout&&c.selectors.checkout.summarySelector?String(c.selectors.checkout.summarySelector):"";if(i){c&&"function"==typeof c.emit&&c.emit(e.opcCartSummaryBeforeUpdate,{selector:i});var a=document.querySelector(i);a instanceof HTMLElement&&(a.outerHTML=o),c&&"function"==typeof c.emit&&c.emit(e.opcCartSummaryUpdated,{selector:i}),function(e){var o=window.prestashop||null,n=e&&"object"===r(e)&&(e.total&&e.total.value||e.total_including_tax&&e.total_including_tax.value)||"",c=o&&o.selectors&&o.selectors.opc&&o.selectors.opc.payAmount?String(o.selectors.opc.payAmount):"",i=c||t.opc.payAmount;if(!n||!i)return;var a=document.querySelector(i);a instanceof HTMLElement&&(a.textContent=String(n))}(n)}}}function a(e){return a="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(e){return typeof e}:function(e){return e&&"function"==typeof Symbol&&e.constructor===Symbol&&e!==Symbol.prototype?"symbol":typeof e},a(e)}function d(e,t){var r=Object.keys(e);if(Object.getOwnPropertySymbols){var o=Object.getOwnPropertySymbols(e);t&&(o=o.filter(function(t){return Object.getOwnPropertyDescriptor(e,t).enumerable})),r.push.apply(r,o)}return r}function p(e){for(var t=1;t<arguments.length;t++){var 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s=r(t.currentTarget),l=r(d),u=c("selectCarrier"),v=String(s.val()||"");if(u&&v){var S=p({delivery_option:v},l.attr("data-id-address")?{}:m());r.post(u,S).done(function(t){if(!t||!1===t.success)return f(l),void a.emit("handleError",{eventType:"opcSelectCarrier",resp:o(t,"Unable to select the delivery method.")});t.preview&&i(t.preview,t.totals),function(e,t){t?e.attr(y,t):e.removeAttr(y)}(l,v),a.emit(e.opcCarrierSelected,t)}).fail(function(e){f(l),a.emit("handleError",{eventType:"opcSelectCarrier",resp:n(e,"Unable to select the delivery method.")})})}else a.emit("handleError",{eventType:"opcSelectCarrier",resp:o(null,"Missing OPC carrier selection payload.")})})}function m(){var e=document.querySelector(l);if(!e)return{};var t=document.querySelector(u)||e;return["id_country","postcode","id_state","city"].reduce(function(e,r){var 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\ No newline at end of file
diff --git a/views/public/opc-guest-init.bundle.js b/views/public/opc-guest-init.bundle.js
index e20e229..2a9fb03 100644
--- a/views/public/opc-guest-init.bundle.js
+++ b/views/public/opc-guest-init.bundle.js
@@ -1,2 +1,2 @@
 /*! For license information please see opc-guest-init.bundle.js.LICENSE.txt */
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\ No newline at end of file
+(()=>{"use strict";const e={opcCarrierSelected:"opcCarrierSelected",opcCarriersUpdated:"opcCarriersUpdated",opcCarriersFailed:"opcCarriersFailed",opcCarriersLoading:"opcCarriersLoading",opcPaymentMethodsLoading:"opcPaymentMethodsLoading",opcPaymentMethodsUpdated:"opcPaymentMethodsUpdated",opcPaymentMethodsFailed:"opcPaymentMethodsFailed",opcPaymentMethodSelected:"opcPaymentMethodSelected",opcGuestInitSuccess:"opcGuestInitSuccess",opcFinalSubmitStarted:"opcFinalSubmitStarted",opcFormValidated:"opcFormValidated",opcBillingSectionToggled:"opcBillingSectionToggled",opcSubmitFailed:"opcSubmitFailed",opcDeliveryAddressUpdated:"opcDeliveryAddressUpdated",opcBillingAddressUpdated:"opcBillingAddressUpdated",opcDeliveryAddressSelected:"opcDeliveryAddressSelected",opcBillingAddressSelected:"opcBillingAddressSelected",opcCartSummaryBeforeUpdate:"opcCartSummaryBeforeUpdate",opcCartSummaryUpdated:"opcCartSummaryUpdated",updatedOpcAddressForm:"updatedOpcAddressForm",opcCarriersRetry:"opcCarriersRetry",opcPaymentMethodsRetry:"opcPaymentMethodsRetry"};const t={opc:{checkout:".one-page-checkout",form:"#opc-form",payButton:"#opc-pay-button",payAmount:"#opc-pay-amount",addressesSection:".js-opc-addresses-section",deliveryMethods:"#opc-delivery-methods",paymentMethods:"#opc-payment-methods",deliverySection:"#opc-delivery-address",deliveryFields:"#opc-delivery-address-fields",billingSection:"#opc-billing-section",billingFields:"#opc-billing-address-fields",deliveryList:"#opc-delivery-address-content-list",billingList:"#opc-billing-address-content-list",useSameAddress:'[name="use_same_address"]',checkoutFooter:".one-page-checkout__footer",contactSection:".js-opc-contact-section",addressRadio:".js-opc-address-radio",addressItem:".opc-address-item",addressLabel:".form-check-label"},templates:{carrierLoader:"#opc-template-loader",carrierError:"#opc-template-carriers-error",paymentLoader:"#opc-template-payment-loader",paymentError:"#opc-template-payment-error"},inputs:{deliveryOption:'input[name="delivery_option"]',paymentOption:'input[name="payment-option"]',email:'input[name="email"]',conditions:'.one-page-checkout 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n=r.name,i=String(r.type||"").toLowerCase();!n||"email"===n||r.disabled||k(r)||["hidden","submit","button","image","reset","file"].includes(i)||("checkbox"!==i?"radio"!==i?t[n]=String(o(r).val()||"").trim():r.checked&&(t[n]=String(r.value||"")):t[n]=r.checked?"1":"0")}),t}(t),s=function(e){var t={};return e.find("".concat('input[type="checkbox"]',"[required]")).each(function(e,o){var r=o.name;r&&!k(o)&&(t[r]=o.checked?"1":"0")}),t}(t),d=v();if(d||!function(e){return Object.values(e).includes("0")}(s)){var u=C(d?{email:a.email}:function(e){for(var t=1;t<arguments.length;t++){var o=null!=arguments[t]?arguments[t]:{};t%2?i(Object(o),!0).forEach(function(t){c(e,t,o[t])}):Object.getOwnPropertyDescriptors?Object.defineProperties(e,Object.getOwnPropertyDescriptors(o)):i(Object(o)).forEach(function(t){Object.defineProperty(e,t,Object.getOwnPropertyDescriptor(o,t))})}return e}({email:a.email},s));if(u!==y&&u!==f){f=u,m&&4!==m.readyState&&m.abort();var l=r("guestInit");""!==l?m=o.post(l,a).done(function(t){if(t&&(t.token||t.static_token)&&window&&window.prestashop){var o=String(t.static_token||t.token||"");""!==o&&(window.prestashop.token=o,window.prestashop.static_token=o,n.token=o,n.static_token=o)}if(t&&t.success){var r=Number(t.id_customer||0);r>0?(b=r,window.prestashop&&(window.prestashop.customer=window.prestashop.customer||{},window.prestashop.customer.id=r,n.customer=window.prestashop.customer),y=C({email:a.email})):y=u,n.emit(e.opcGuestInitSuccess,{resp:t})}else t&&t.errors&&Array.isArray(t.errors.token)&&t.errors.token.length>0?y=u:t&&!1===t.success&&n.emit("handleError",{eventType:"opcGuestInit",resp:t})}).fail(function(e){e&&"abort"===e.statusText||n.emit("handleError",{eventType:"opcGuestInit",resp:e})}).always(function(){f=""}):n.emit("handleError",{eventType:"opcGuestInit",resp:{errors:{"":["Missing OPC guest init URL."]}}})}}else F()}else F()}}function M(){if(!g){var 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\ No newline at end of file
diff --git a/views/public/opc-payment-list.bundle.js b/views/public/opc-payment-list.bundle.js
new file mode 100644
index 0000000..7cde58c
--- /dev/null
+++ b/views/public/opc-payment-list.bundle.js
@@ -0,0 +1 @@
+(()=>{"use strict";const e={opcCarrierSelected:"opcCarrierSelected",opcCarriersUpdated:"opcCarriersUpdated",opcCarriersFailed:"opcCarriersFailed",opcCarriersLoading:"opcCarriersLoading",opcPaymentMethodsLoading:"opcPaymentMethodsLoading",opcPaymentMethodsUpdated:"opcPaymentMethodsUpdated",opcPaymentMethodsFailed:"opcPaymentMethodsFailed",opcPaymentMethodSelected:"opcPaymentMethodSelected",opcGuestInitSuccess:"opcGuestInitSuccess",opcFinalSubmitStarted:"opcFinalSubmitStarted",opcFormValidated:"opcFormValidated",opcBillingSectionToggled:"opcBillingSectionToggled",opcSubmitFailed:"opcSubmitFailed",opcDeliveryAddressUpdated:"opcDeliveryAddressUpdated",opcBillingAddressUpdated:"opcBillingAddressUpdated",opcDeliveryAddressSelected:"opcDeliveryAddressSelected",opcBillingAddressSelected:"opcBillingAddressSelected",opcCartSummaryBeforeUpdate:"opcCartSummaryBeforeUpdate",opcCartSummaryUpdated:"opcCartSummaryUpdated",updatedOpcAddressForm:"updatedOpcAddressForm",opcCarriersRetry:"opcCarriersRetry",opcPaymentMethodsRetry:"opcPaymentMethodsRetry"};const o={opc:{checkout:".one-page-checkout",form:"#opc-form",payButton:"#opc-pay-button",payAmount:"#opc-pay-amount",addressesSection:".js-opc-addresses-section",deliveryMethods:"#opc-delivery-methods",paymentMethods:"#opc-payment-methods",deliverySection:"#opc-delivery-address",deliveryFields:"#opc-delivery-address-fields",billingSection:"#opc-billing-section",billingFields:"#opc-billing-address-fields",deliveryList:"#opc-delivery-address-content-list",billingList:"#opc-billing-address-content-list",useSameAddress:'[name="use_same_address"]',checkoutFooter:".one-page-checkout__footer",contactSection:".js-opc-contact-section",addressRadio:".js-opc-address-radio",addressItem:".opc-address-item",addressLabel:".form-check-label"},templates:{carrierLoader:"#opc-template-loader",carrierError:"#opc-template-carriers-error",paymentLoader:"#opc-template-payment-loader",paymentError:"#opc-template-payment-error"},inputs:{deliveryOption:'input[name="delivery_option"]',paymentOption:'input[name="payment-option"]',email:'input[name="email"]',conditions:'.one-page-checkout input[name^="conditions_to_approve["][required]'},modals:{address:"#opc-address-modal, #modal-delivery, #modal-invoice"}};function t(e){return t="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(e){return typeof e}:function(e){return e&&"function"==typeof Symbol&&e.constructor===Symbol&&e!==Symbol.prototype?"symbol":typeof e},t(e)}function r(e,o){return null===(r=e)||"object"!==t(r)||Array.isArray(r)?{errors:{"":[o]}}:e;var r}function d(e){var o=window&&"object"===t(window.ps_onepagecheckout)&&window.ps_onepagecheckout?window.ps_onepagecheckout:null;return o&&o.urls&&o.urls[e]?String(o.urls[e]):""}!function(){var t=window.$||window.jQuery,a=window.prestashop||{};if(t){var n=o.opc.paymentMethods,i=o.opc.checkout,c=0;t(y),t(document).on("click",'[data-opc-action="retry-payment"]',function(e){e.preventDefault(),y()}),a.on(e.opcCarrierSelected,y),a.on(e.opcBillingAddressUpdated,y),a.on(e.opcGuestInitSuccess,y),a.on(e.opcPaymentMethodsRetry,y),a.on(e.opcCarriersLoading,function(){c+=1,m()}),a.on(e.opcCarriersFailed,function(){var t=p();c+=1,t.length&&t.html(s(o.templates.paymentError.replace("#",""))),a.emit(e.opcPaymentMethodsFailed,{error:"carrier fetch failed"})})}function s(e){var o=document.querySelector("#".concat(e));return o?o.innerHTML:""}function p(){return t(n)}function l(e,t){var r=document.querySelector("".concat(e," ").concat(o.opc.addressRadio,'[name="').concat(t,'"]:checked')),d=r?String(r.getAttribute("value")||""):"";return d&&"new_address"!==d?d:""}function m(){var t=p();t.length&&(t.html(s(o.templates.paymentLoader.replace("#",""))),a.emit(e.opcPaymentMethodsLoading,{}))}function u(e){var t,r,d,a,n,c=document.querySelector(i);if(!c||!e)return"";var s=new URL(e,window.location.origin),p=(null===(t=c.querySelector('[name="id_country"]'))||void 0===t?void 0:t.value)||(null===(r=c.querySelector('[name="delivery_id_country"]'))||void 0===r?void 0:r.value)||"",m=(null===(d=c.querySelector('[name="invoice_id_country"]'))||void 0===d?void 0:d.value)||"",u=l(o.opc.deliveryList,"id_address_delivery")||(null===(a=c.querySelector('[name="id_address_delivery"]'))||void 0===a?void 0:a.value)||"",y=l(o.opc.billingList,"id_address_invoice")||(null===(n=c.querySelector('[name="id_address_invoice"]'))||void 0===n?void 0:n.value)||"";return p&&s.searchParams.set("id_country",p),m&&s.searchParams.set("invoice_id_country",m),u&&s.searchParams.set("id_address_delivery",u),y&&s.searchParams.set("id_address_invoice",y),s.toString()}function y(){var n=p(),i=u(d("paymentMethods"));if(n.length&&i){var l=++c;m(),t.get(i).done(function(t){if(l===c){if(!t||!1===t.success){var d=r(t,"Unable to load 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\ No newline at end of file
diff --git a/views/public/opc-payment-select.bundle.js b/views/public/opc-payment-select.bundle.js
new file mode 100644
index 0000000..5df510d
--- /dev/null
+++ b/views/public/opc-payment-select.bundle.js
@@ -0,0 +1 @@
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\ No newline at end of file
diff --git a/views/public/opc-submit.bundle.js b/views/public/opc-submit.bundle.js
new file mode 100644
index 0000000..c22d3ff
--- /dev/null
+++ b/views/public/opc-submit.bundle.js
@@ -0,0 +1,2 @@
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n=t.id,o=document.querySelector("#pay-with-".concat(n,"-form")),r=o?o.querySelector("form"):null;c.emit(e.opcFinalSubmitStarted),r instanceof HTMLFormElement?HTMLFormElement.prototype.submit.call(r):O("Missing rendered payment form for the selected option.")}function U(e,t){var n=new FormData(e);if(function(e){H().forEach(function(t){t instanceof HTMLInputElement&&t.name&&("checkbox"!==t.type?""!==String(t.value||"").trim()&&e.set(t.name,t.value):t.checked&&e.set(t.name,t.value))})}(n),!n.has("static_token")){var o,r,a=(null===(o=window.prestashop)||void 0===o?void 0:o.static_token)||(null===(r=window.prestashop)||void 0===r?void 0:r.token)||"";""!==a&&n.set("static_token",a)}return t instanceof HTMLInputElement&&t.dataset.moduleName&&n.set("paymentMethod",t.dataset.moduleName),n}function V(e){return function(e){return!!e.checkValidity()||(e.reportValidity(),!1)}(e)&&function(){var e,t=d(H());try{for(t.s();!(e=t.n()).done;){var n=e.value;if(n instanceof HTMLInputElement&&n.required&&!n.checkValidity())return n.reportValidity(),!1}}catch(e){t.e(e)}finally{t.f()}return!0}()?F()?q(e):(C(),{isValid:!1,paymentRadio:null}):{isValid:!1,paymentRadio:null}}function R(){var e=r("opcSubmit");return e||(O("Missing OPC submit URL."),"")}function x(e,t){return D.apply(this,arguments)}function D(){return(D=l(i().m(function e(t,n){var o;return i().w(function(e){for(;;)switch(e.n){case 0:return e.n=1,fetch(t,{method:"POST",credentials:"same-origin",headers:{Accept:"application/json"},body:n});case 1:return o=e.v,e.a(2,o.json().catch(function(){return{}}))}},e)}))).apply(this,arguments)}function G(e){return e&&e.reload?(window.location.href=e.checkout_url||window.location.href,!0):(P(e),!0)}function N(e,t){return $.apply(this,arguments)}function $(){return($=l(i().m(function e(t,n){var o,r,a;return i().w(function(e){for(;;)switch(e.n){case 0:return e.n=1,j();case 1:if(r=e.v,"function"!=typeof(a=null===(o=c.checkout)||void 0===o?void 0:o.onCheckOrderableCartResponse)){e.n=3;break}if(!a(r,{})){e.n=2;break}return e.a(2);case 2:e.n=4;break;case 3:if(!r||!0!==r.errors||!r.cartUrl){e.n=4;break}return window.location.href=r.cartUrl,e.a(2);case 4:if(!(n instanceof HTMLInputElement)){e.n=5;break}return I(n),e.a(2);case 5:window.location.href=t.checkout_url||window.prestashop.urls.pages.order;case 6:return e.a(2)}},e)}))).apply(this,arguments)}function Q(e){return z.apply(this,arguments)}function z(){return(z=l(i().m(function t(n){var o,r,a,u,l,d;return i().w(function(t){for(;;)switch(t.p=t.n){case 0:if(!L){t.n=1;break}return t.a(2);case 1:if((o=V(n)).isValid){t.n=2;break}return t.a(2);case 2:if(r=R()){t.n=3;break}return t.a(2);case 3:return a=T(),u=U(n,o.paymentRadio),L=!0,a instanceof HTMLButtonElement&&(a.disabled=!0),t.p=4,t.n=5,x(r,u);case 5:if((l=t.v)&&!0===l.success){t.n=6;break}return G(l),t.a(2);case 6:return t.n=7,N(l,o.paymentRadio);case 7:t.n=9;break;case 8:t.p=8,d=t.v,c.emit("handleError",{eventType:"opcSubmit",resp:{}}),c.emit(e.opcSubmitFailed,{error:d});case 9:return t.p=9,L=!1,C(),t.f(9);case 10:return t.a(2)}},t,null,[[4,8,9,10]])}))).apply(this,arguments)}function J(e,t,n){(e instanceof HTMLElement||e instanceof HTMLFormElement)&&e.querySelectorAll(t).forEach(function(e){(e instanceof HTMLInputElement||e instanceof HTMLSelectElement||e instanceof HTMLTextAreaElement)&&"1"!==e.dataset[n]&&(e.addEventListener("change",C),e.dataset[n]="1")})}function K(e){J(e,S,"opcDeliveryValidationBound");var t=B();t instanceof HTMLElement&&J(t,b,"opcPaymentValidationBound");var n=k();(n instanceof HTMLElement||n instanceof Document)&&J(n instanceof Document?n.documentElement:n,'input[name^="conditions_to_approve"]',"opcConditionsValidationBound")}function W(){var e=E(),t=T();e instanceof HTMLFormElement&&t instanceof HTMLButtonElement&&(!function(e,t){e.dataset.opcSubmitInputBound||(e.addEventListener("input",C),e.dataset.opcSubmitInputBound="1"),e.dataset.opcSubmitChangeBound||(e.addEventListener("change",C),e.dataset.opcSubmitChangeBound="1"),e.dataset.opcSubmitHandlerBound||(e.addEventListener("submit",function(t){t.preventDefault(),Q(e)}),e.dataset.opcSubmitHandlerBound="1"),t.dataset.opcSubmitHandlerBound||(t.addEventListener("click",function(n){n.preventDefault(),L||t.disabled||Q(e)}),t.dataset.opcSubmitHandlerBound="1")}(e,t),K(e))}}()})();
\ No newline at end of file
diff --git a/views/public/opc-submit.bundle.js.LICENSE.txt b/views/public/opc-submit.bundle.js.LICENSE.txt
new file mode 100644
index 0000000..10ceb17
--- /dev/null
+++ b/views/public/opc-submit.bundle.js.LICENSE.txt
@@ -0,0 +1,26 @@
+/*! regenerator-runtime -- Copyright (c) 2014-present, Facebook, Inc. -- license (MIT): https://github.com/babel/babel/blob/main/packages/babel-helpers/LICENSE */
+
+/**
+ * Copyright since 2007 PrestaShop SA and Contributors
+ * PrestaShop is an International Registered Trademark & Property of PrestaShop SA
+ *
+ * NOTICE OF LICENSE
+ *
+ * This source file is subject to the Open Software License (OSL 3.0)
+ * that is bundled with this package in the file LICENSE.md.
+ * It is also available through the world-wide-web at this URL:
+ * https://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to
+ * obtain it through the world-wide-web, please send an email
+ * to license@prestashop.com so we can send you a copy immediately.
+ *
+ * DISCLAIMER
+ *
+ * Do not edit or add to this file if you wish to upgrade PrestaShop to newer
+ * versions in the future. If you wish to customize PrestaShop for your
+ * needs please refer to https://devdocs.prestashop.com/ for more information.
+ *
+ * @author    PrestaShop SA and Contributors <contact@prestashop.com>
+ * @copyright Since 2007 PrestaShop SA and Contributors
+ * @license   https://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ */
diff --git a/views/webpack.config.js b/views/webpack.config.js
index 053e344..a7915ec 100644
--- a/views/webpack.config.js
+++ b/views/webpack.config.js
@@ -8,8 +8,14 @@ const TerserPlugin = require('terser-webpack-plugin');
 
 module.exports = {
   entry: {
+    'opc-submit': './js/opc-submit.js',
     'opc-guest-init': './js/opc-guest-init.js',
     'opc-address': './js/opc-address.js',
+    'opc-address-modal': './js/opc-address-modal.js',
+    'opc-carrier-list': './js/opc-carrier-list.js',
+    'opc-carrier-select': './js/opc-carrier-select.js',
+    'opc-payment-list': './js/opc-payment-list.js',
+    'opc-payment-select': './js/opc-payment-select.js',
   },
   output: {
     path: path.resolve(__dirname, 'public'),