shopify-functionslisted

# Shopify Functions Shopify Functions are WebAssembly (WASM) units of business logic that extend the Shopify checkout, order, and fulfillment pipelines. They execute in a sandboxed runtime on Shopify's servers and have strict constraints: 5ms execution window, 256KB binary limit, no async I/O, no outbound HTTP to unknown hosts, and 30-point GraphQL query complexity ceiling. ## Architecture & Execution Model **Function Lifecycle:** 1. Merchant installs your app; metafield definitions are registered 2. App reads merchant configuration from metafields (Shop, Product, Collection scopes) 3. On checkout/order event, Shopify invokes your function with Input JSON payload 4. Function executes WASM bytecode, applies business logic, returns JSON output 5. Output mutations are applied atomically to the checkout/order state **Execution Constraints (Hard Limits):** - Max execution time: 5ms (timeout failure = no operation) - Max binary size: 256KB gzipped - Max instructions: 11 million - Max memory: 256KB heap - Max output JSON: 256KB - Max GraphQL query complexity: 30 points (estimate 1pt per simple field) - No async I/O, no event loops, no multi-threading - No network access except allowed_hosts (NEW 2025-01) - Deterministic execution only **Why WASM?** Shopify Functions run in Wasmtime, a fast WebAssembly runtime. This provides: - Language flexibility: Compile Rust, JavaScript (via AssemblyScript), or Go to WASM - Isolation: No access to host filesystem, process, or network (except