Express.js

Express is the minimal, unopinionated web framework for Node.js. It is a thin layer over node:http: it adds a router, a middleware pipeline, a richer request and response, view rendering and a handful of conventions, and leaves everything else (validation, persistence, authentication, project layout) to you and to the ecosystem. Most of the work is done by small, separately versioned modules: router and path-to-regexp for routing, body-parser for request bodies, serve-static and send for files, finalhandler for the last response, and proxy-addr for proxy trust. It is an OpenJS Foundation project and, years after its first release in 2010, the framework most other Node.js frameworks are measured against or built on, including NestJS through its default HTTP platform.

This section is for developers who:

Every example builds Bookshelf, the same domain used by the Node.js, NestJS, FastAPI and Next.js sections, so the stacks can be compared. It starts as a hello-world app and grows into a bookshelf-api JSON API (/api/v1/books, /reviews and /authors) with validation, problem-details errors, pagination and filtering. It persists data with node:sqlite first, then PostgreSQL through pg or Prisma and MongoDB through Mongoose. It adds a server-rendered admin area with a template engine, sessions and Passport login, JWT-protected endpoints with CORS for a single-page application, cover uploads with multer and downloads with res.download, a GraphQL endpoint, a live "new review" feed over Server-Sent Events and Socket.IO, supertest and node:test suites, a Dockerfile, health checks and graceful shutdown. Pages build on each other, but each can be read on its own.

The pages are ordered so that each one builds on the previous ones:

Source: Express: Express examples

The expressjs/express repository ships 25 runnable applications in its examples directory (described on the official examples page). Each is explained, modernised for Express 5 and mapped to the Bookshelf scenario on the page below. The Getting Started page shows how to run them.

Existing pages are linked rather than repeated; the Express pages add only the framework layer.

Every source used to generate this section, each linked to its official website. Individual pages list the subset they derive from under their own == References heading. The books below were consulted for concept coverage, narrative and structure only; every code example is written against the current official documentation, which wins wherever a book differs, and each page says where a book is outdated.