nodejs-backend-patterns

Use a layered architecture with controllers handling HTTP requests, services containing business logic, and repositories managing data access. Wire dependencies through a DI container so each layer can be tested and replaced independently.

Create an authenticate middleware that extracts the Bearer token from the Authorization header and verifies it with jsonwebtoken. Attach the decoded payload to the request object, and issue short-lived access tokens (15m) alongside 7-day refresh tokens.

Express offers a minimalist, widely adopted ecosystem, while Fastify provides higher throughput with built-in schema validation and Pino logging. Choose Fastify for performance-sensitive services and Express for maximum middleware compatibility.

Acquire a client from the pg Pool, run BEGIN, execute your queries, then COMMIT on success or ROLLBACK on error, always releasing the client in a finally block. This keeps multi-step writes like order creation atomic.

Redis-backed rate limiting via rate-limit-redis shares counters across multiple server instances, so limits hold under horizontal scaling. In-memory stores reset per process and per instance, allowing clients to exceed intended quotas.

Layered class architecture adds boilerplate and indirection that may be excessive for small services or prototypes. For simple CRUD APIs, a flat route-handler structure with direct database calls can be faster to ship and easier to read.