Express
A minimal, unopinionated web framework for Node.js.
CurrentintermediateFull course available
Overview
Express is the most widely used Node.js web framework: a thin, unopinionated layer over Node's HTTP module adding routing, middleware, and request/response helpers, without dictating project structure the way a full framework (like Django or Spring Boot) does.
- What it is
- A minimal Node.js web framework for routing HTTP requests and composing middleware.
- Why it's used
- For its simplicity, huge middleware ecosystem, and flexibility -- a good fit when you want control over structure rather than a full framework's conventions.
- Where it fits
- Built on top of Node.js; often the first backend framework a JavaScript developer learns. The Node.js and Express Backend Development course covers this in depth: routing, middleware, validation, structured errors, security boundaries, and testing.
Core concepts
- Routing (app.get, app.post)
- Middleware functions
- Request and response objects
- Error handling middleware
Example
Middleware and route handlers form a pipeline each request passes through -- Express's core abstraction is composing small functions rather than a monolithic request handler.
const express = require("express");
const app = express();
app.get("/users/:id", (req, res) => {
res.json({ id: req.params.id });
});
app.listen(3000);Common use cases
- REST APIs
- Server-rendered web applications
- Backend-for-frontend services
Project ideas
- A small REST API with GET/POST routes backed by an in-memory data store