Express

Express is the most widely deployed Node.js web framework, providing a minimal, unopinionated layer of routing, middleware, and HTTP utilities on top of the built-in http module. Express defined the middleware pattern that nearly every Node web framework since has adopted.

Core concepts

• Routes. Map HTTP methods and URL paths to handler functions.
• Middleware. Functions of the form (req, res, next) => void that compose into a request pipeline.
• Request and response. Augmented Node.js objects with helpers like res.json(), req.params, req.body.
• Routers. Modular sub-applications mounted on path prefixes.

Common middleware

• express.json(), express.urlencoded() for body parsing
• cors, helmet, compression for security and performance
• morgan, pino-http for request logging
• express-rate-limit, express-validator for protection and validation

Alternatives

• Fastify. Higher throughput, schema-driven, growing share.
• Koa. Modern async-first design from the Express authors.
• NestJS. Opinionated, Angular-inspired structure on top of Express or Fastify.
• Hono. Edge-first, runs on Bun, Deno, Cloudflare Workers, Node.