Express

About Express

Express.js is a minimal, unopinionated web framework for Node.js, created by TJ Holowaychuk and released in 2010. Express is the most downloaded npm package after the Node.js core modules and forms the backbone of the MEAN/MERN stacks. Its philosophy mirrors Flask in Python: provide routing, middleware, and HTTP utilities without imposing application structure. An Express app can be running in under 5 lines of code. Express middleware pipeline is its core abstraction — functions that process requests sequentially, enabling authentication, logging, rate limiting, body parsing, and CORS as composable layers. Express powers APIs at Uber, IBM, Fox Sports, and thousands of startups. Despite being over a decade old with no breaking changes since v4, Express remains the most used Node.js framework by raw usage due to its familiarity and npm ecosystem. Express 5.0 (finally stable after years in beta) adds async error handling and Promise support to route handlers. Fastify has emerged as a modern alternative — 2–3x faster and TypeScript-first — while NestJS provides an opinionated Angular-inspired structure on top of Express or Fastify. Express's weakness is its lack of opinions: teams must choose and integrate validation libraries, ORM, authentication strategies, and project structure themselves. For teams wanting structure, NestJS or Adonis.js are better; for teams wanting simplicity and control, Express remains the go-to Node.js framework.