nodejs-backend-patterns

Layered architecture in a Node.js backend separates concerns into controllers, services, repositories, and models. This pattern isolates business logic from data access and routing, making Express or Fastify applications easier to test and maintain.

JWT authentication in Express uses middleware patterns to validate tokens and protect routes. Implementing token refresh flows involves issuing short-lived access tokens and securely handling refresh tokens to maintain user sessions securely.

Error handling in a Fastify microservice requires centralized middleware to catch and format exceptions consistently. Database integration uses connection patterns for PostgreSQL or MongoDB, ensuring reliable transactions alongside proper error responses.

Dependency injection and caching patterns can be applied to Node.js REST APIs to decouple components and optimize response times. Injecting services into controllers increases testability, while caching reduces database load and improves backend performance.

Middleware patterns for rate limiting and validation intercept incoming requests to enforce quotas and validate payloads. In Express or Fastify, these patterns protect endpoints from abuse and ensure data integrity before reaching the service layer.

Testing strategies for Node.js backend patterns apply to both REST and GraphQL servers. The guidance covers testing layered components including controllers, services, and repositories, ensuring validation across microservices and authentication flows.