Shopify platform development. Stack: Shopify CLI, GraphQL/REST APIs, Polaris UI, Liquid templating. Capabilities: app development (OAuth), checkout UI extensions, admin UI extensions, POS extensions, theme development, webhooks, billing API, product/order/customer management. Actions: build, extend, customize, integrate Shopify apps/themes. Keywords: Shopify, Shopify CLI, GraphQL Admin API, REST API, Polaris, Liquid, checkout extension, admin extension, POS extension, theme, webhook, billing API, OAuth, app bridge, metafields, product, order, customer, storefront, hydrogen, oxygen. Use when: building Shopify apps, customizing checkout, creating admin interfaces, developing themes, integrating payments, managing store data via APIs, extending Shopify functionality.