Node.js Backend Skill --- Project Structure --- API Design Route Handler Pattern Dependency Injection at Composition Root --- Error Handling Domain Errors Global Error Handler --- Database Patterns Repository Pattern Transactions --- Configuration Validated Config --- Testing Unit Tests (Core) Integration Tests (API) --- Node.js Anti-Patterns - ❌ Callback hell - use async/await - ❌ Unhandled promise rejections - always catch or let error handler catch - ❌ Blocking the event loop - offload heavy computation - ❌ Secrets in code - use environment variables - ❌ SQL string concatenation - use para…