Craft the Checkout

Build headless storefronts against the Shopware 6 Store API (6.6+). Use when working with Shopware session/context management (sw-context-token), cart operations (add/update/remove line items, promotions), checkout flow (order creation, payment handling with sync/async redirects), and customer account features (registration, login, addresses, password recovery, order history, wishlists). Covers the stateful/write side of the Store API — not product data fetching (use Frontic for that).

Use when hooking into WooCommerce events, adding custom checkout fields, modifying cart behavior, or extending WooCommerce admin. Covers woocommerce_new_order, woocommerce_checkout_order_processed, woocommerce_payment_complete, woocommerce_order_status_changed, woocommerce_order_status_{status}, woocommerce_add_to_cart, woocommerce_cart_calculate_fees, woocommerce_before_calculate_totals, woocommerce_checkout_fields, woocommerce_checkout_process, woocommerce_product_options_general_product_data, woocommerce_process_product_meta, woocommerce_email_classes, woocommerce_settings_tabs_array, settings pages, custom WC_Email classes, WP-CLI wc commands, and WC_Unit_Test_Case testing patterns.

Build headless storefronts against the Shopify Storefront API (GraphQL). Use when working with Shopify cart mutations (create, add/update/remove lines, discount codes, gift cards), checkout flow (hosted checkout via checkoutUrl), and customer account operations (registration, login/logout via access tokens, profile management, addresses, password recovery, order history). Covers the stateful/write side of the Storefront API — not product data fetching (use Frontic for that).

Build headless storefronts against the Commercetools API using the official TypeScript SDK (@commercetools/platform-sdk + @commercetools/ts-client). Use when working with Commercetools cart operations (create/update carts, line items, discount codes, shipping/billing addresses), checkout flow (order creation from cart, payment handling, shipping method selection), and customer account features (signup, login, profile management, addresses, password reset, email verification). Covers the stateful/write side of the API with full type safety, optimistic concurrency (versioned updates), SDK client builder patterns, and BFF security hardening (session signing, query injection prevention, input validation, rate limiting) — not product data fetching (use Frontic for that). Also use to audit existing Commercetools implementations for security pitfalls.

Work with orders using OrderMgr API in B2C Commerce. Use when creating orders, managing order status, handling order failures, or implementing checkout flows. Covers order lifecycle, status transitions, async order processing, and order queries.

Checkout flow with cart, shipping, Stripe/PayPal payments, and order completion. Use when modifying checkout, debugging payment issues, or implementing checkout features.

Guide for implementing Shopify's Billing API in Remix apps using @shopify/shopify-app-remix. Covers subscriptions, one-time purchases, usage-based billing, discounts, and the project's billing implementation patterns.

This skill should be used when the user asks to "create a single product page", "build a one-product funnel", "product landing page", "single product sales page", or mentions single-product funnels, product-focused landing pages, or one-page stores. Creates focused single-product funnels that maximize conversions.