How to Build a REST API with Node.js and Express (2026)

You need Node.js installed and a code editor. That's it. No database, no framework beyond Express, no build tools. Check if Node is already on your machine: open a terminal and run node --version. If you see a version number like v20.x or higher, you're set. If not, download the LTS version from nodejs.org and install it. Node ships with npm, the package manager you'll use to pull in Express. One thing worth knowing up front: a REST API is just a program that listens for HTTP requests and sends back data, usually as JSON. When your phone app loads your messages, it's hitting a REST API. You're about to build a small version of the same thing.

Make a folder and turn it into a Node project. In your terminal: mkdir my-api cd my-api npm init -y The npm init -y command creates a package.json file, which tracks your project's dependencies and settings. The -y flag accepts all the defaults so you don't have to answer questions. Now install Express: npm install express This pulls Express into a node_modules folder and records it in package.json. Express is the most widely used web framework for Node. It handles the low-level HTTP work so you can focus on your routes.

Create a file called server.js and add this: const express = require('express'); const app = express(); app.use(express.json()); const PORT = 3000; app.listen(PORT, () => console.log(`API running on port ${PORT}`)); Three things are happening. You import Express and create an app. You tell the app to parse incoming JSON with express.json(), which means request bodies show up as a normal JavaScript object on req.body. Then you start the server listening on port 3000. Run it with node server.js. You should see your log message. The server is up, but it doesn't answer any routes yet. That's next.

A REST API maps HTTP methods to actions on a resource. For a list of tasks, the standard set looks like this: GET /tasks reads all tasks, POST /tasks creates one, PUT /tasks/:id updates one, DELETE /tasks/:id removes one. Here's a simple version using an in-memory array so you don't need a database yet: let tasks = [{ id: 1, title: 'Learn Express' }]; app.get('/tasks', (req, res) => res.json(tasks)); app.post('/tasks', (req, res) => { const task = { id: Date.now(), title: req.body.title }; tasks.push(task); res.status(201).json(task); }); app.delete('/tasks/:id', (req, res) => { tasks = tasks.filter(t => t.id !== Number(req.params.id)); res.status(204).end(); }); Notice req.params.id pulls the id out of the URL, and req.body.title reads the JSON you posted. The res.status() calls set the right HTTP status: 201 for created, 204 for deleted with no content.

Restart the server (stop with Ctrl+C, run node server.js again) and hit your routes. The quickest way is curl from another terminal: curl http://localhost:3000/tasks curl -X POST http://localhost:3000/tasks -H "Content-Type: application/json" -d '{"title":"Write tests"}' The first command lists your tasks. The second creates one and returns it. If you prefer a graphical tool, Postman or the Thunder Client extension for VS Code do the same thing with a friendlier interface. When a POST returns your new task with an id, your API works. You now have all four CRUD operations answering real HTTP requests.

A real API needs to fail gracefully. Add a check so a request for a missing task returns 404 instead of crashing: app.get('/tasks/:id', (req, res) => { const task = tasks.find(t => t.id === Number(req.params.id)); if (!task) return res.status(404).json({ error: 'Task not found' }); res.json(task); }); From here, the natural next steps are swapping the in-memory array for a real database (PostgreSQL with a library like Drizzle or Prisma is a common choice), adding input validation so bad data gets rejected early, and splitting routes into their own files as the project grows. If you want a guided path through backend work, our /learn/backend page pulls together free courses that cover exactly this progression, and /guides/how-to-become-a-backend-developer maps the wider skill set.