How-To Guide

How to Install Express.js

Express is the most popular Node.js web framework. It's how you build APIs, web servers, and full-stack apps in JavaScript. Here's how to install it in 10 minutes.

📋 What You'll Need

Node.js 18+ installed — see our Install Node.js guide
A code editor (VS Code recommended)
A terminal
10 minutes of your time

✅ Express is free and open source.

🚂 What Is Express?

Express is a minimal Node.js framework that gives you:

Routing — map URLs to functions
Middleware — chain functions that process requests
Request/response helpers — parse JSON, send files, set headers
Template support — render HTML from data

It's the foundation of most Node backends and runs behind GitHub, Uber, and thousands of APIs.

Create a Project Folder

Open your terminal and run:

mkdir my-express-app
cd my-express-app

Initialize npm

This creates a package.json file — the manifest of your project:

npm init -y

The -y accepts all defaults. You can edit it later.

Install Express

npm install express

This downloads Express and adds it to your node_modules folder. It also adds it to package.json under dependencies.

💡 Using pnpm? pnpm add express does the same thing, faster.

Create Your First Server

Create a file called index.js and add:

const express = require('express');
const app = express();

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

app.listen(3000, () => {
    console.log('Server running at http://localhost:3000');
});

Run it:

node index.js

Open http://localhost:3000 in your browser. You should see Hello from Express! 🎉

🧠 Essential Express Patterns

// Different HTTP methods
app.get('/users', handler);
app.post('/users', handler);
app.put('/users/:id', handler);
app.delete('/users/:id', handler);

// Return JSON
app.get('/api/data', (req, res) => {
    res.json({ message: 'Hello' });
});

// Read URL parameters
app.get('/users/:id', (req, res) => {
    res.send(`User ID: ${req.params.id}`);
});

// Read query strings (?name=Sarah)
app.get('/search', (req, res) => {
    res.send(`Searching: ${req.query.q}`);
});

// Parse JSON bodies
app.use(express.json());

app.post('/api/users', (req, res) => {
    console.log(req.body);
    res.json({ received: true });
});