Express — Fast Unopinionated Minimalist Web Framework for Node.js

What Express Does

• Routing — path, method, regex matching
• Middleware — composable request/response pipeline
• Request/response — enhanced req/res objects
• Error handling — centralized error middleware
• Static files — express.static() built in
• Template engines — Pug, EJS, Handlebars via app.engine()
• JSON parsing — express.json() middleware
• Cookies/sessions — via cookie-parser and express-session
• CORS — via cors middleware
• Express 5 — native async error handling (upcoming)

Architecture

Middleware stack: each app.use() adds a function to the pipeline. Request enters, flows through middleware in order, and hits the matching route handler. Router is a mini-app with its own middleware and routes. Error middleware has 4 arguments (err, req, res, next).

Self-Hosting

# Production
NODE_ENV=production node server.js

# PM2
npm i -g pm2
pm2 start server.js -i max
pm2 startup && pm2 save

# Docker
FROM node:20-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production
COPY . .
CMD ["node", "server.js"]

Key Features

• Minimal and unopinionated
• Middleware-based architecture
• Huge middleware ecosystem
• Template engine support
• Static file serving
• HTTP utility methods
• Easy to learn
• Express Generator for scaffolding
• Works with any Node.js version

Comparison

FAQ

Q: Is Express outdated? A: No. Fastify and Hono perform better, but Express has the largest ecosystem, the most tutorials, and the richest middleware. Many production apps still use it and run stably. Express 5 is under development.

Q: TypeScript support? A: With @types/express you get full types. Many projects use ts-node or tsx during development.

Q: Error handling? A: Express 4 requires wrapping async handlers with try-catch or using express-async-errors. Express 5 natively catches async throws and forwards them to error middleware.

Sources

• Docs: https://expressjs.com
• GitHub: https://github.com/expressjs/express
• License: MIT