Express

Express is a small web framework for Node.js. It handles the plumbing of an HTTP server — matching URLs and methods to handler functions, reading requests and sending responses — and leaves almost every other decision to you.

The core idea is middleware: an Express app is a chain of functions that each receive the request, the response and a next callback, and either answer the request or pass it along. Routing, body parsing, sessions, CORS and error handling are all middleware, and express.Router() lets you group routes into modules. Express 5 forwards errors thrown in async handlers to your error middleware automatically, so you no longer need to wrap every handler in a try/catch.

For a small team, the practical draw is the catalog: the Express team maintains modules such as body-parser, cors, multer, session and compression, and the docs list many popular third-party middleware modules on top. It runs anywhere Node runs — a VPS, a container or a platform service — and the docs recommend a process manager in production so the app restarts after a crash.

Express has no opinion on databases, models, authentication, validation or project structure; you assemble each one yourself. It is written in JavaScript and does not ship its own TypeScript types, so typed projects rely on the community @types/express package.