Express Intro

Express is the most popular Node web framework — a thin layer over node:http that adds routing, middleware, and helpers. Most Node APIs in production use it (or a descendant).

Install

npm install express

Hello, Express

import express from "express";

const app = express();

app.get("/", (req, res) => {
  res.send("Hello, Express!");
});

app.get("/api/users", (req, res) => {
  res.json([{ id: 1, name: "Ada" }]);
});

app.listen(3000, () => console.log("up on :3000"));

Compare with raw node:http:

• app.get(path, handler) instead of method/URL switches
• res.send() and res.json() instead of manual writeHead/end
• app.use(...) for middleware

What Express Gives You

• Pattern-based routing (/users/:id)
• Middleware chain (auth, logging, body-parsing, error handling)
• req.params, req.query, req.body (with body-parser middleware)
• res.json, res.status, res.redirect, res.cookie
• A vast plugin ecosystem (auth, CORS, validation, sessions, …)

What Express Doesn’t Give You

• Type safety (it’s plain JS — for TS, write your own types)
• Built-in validation (use Zod or Joi)
• Performance crown (Fastify is faster)
• Modern features (Server-Sent Events, HTTP/2 streams)

For greenfield projects in 2026, consider Fastify or Hono — faster, schema-first, modern. But Express still dominates job postings, docs, and Stack Overflow answers. Learning it pays off.

Versions

Express 4 has been the standard for a decade. Express 5 went stable recently — drops some legacy quirks, adds promise-aware error handling. This track uses Express 5 patterns; everything also works on 4.

Up Next

Routes — Express’s bread and butter.