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

Build a REST API in Minutes

Express is the most popular Node.js web framework. This guide builds a working CRUD API from scratch.

Step 1: Setup

mkdir my-api && cd my-api
npm init -y
npm install express

Step 2: Basic Server

const express = require("express");
const app = express();
app.use(express.json()); // parse JSON bodies

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

Step 3: CRUD Routes

let users = [{ id: 1, name: "Sara" }];

// READ all
app.get("/users", (req, res) => res.json(users));

// READ one
app.get("/users/:id", (req, res) => {
  const user = users.find(u => u.id === +req.params.id);
  if (!user) return res.status(404).json({ error: "Not found" });
  res.json(user);
});

// CREATE
app.post("/users", (req, res) => {
  const user = { id: Date.now(), ...req.body };
  users.push(user);
  res.status(201).json(user);
});

// UPDATE
app.put("/users/:id", (req, res) => {
  const i = users.findIndex(u => u.id === +req.params.id);
  users[i] = { ...users[i], ...req.body };
  res.json(users[i]);
});

// DELETE
app.delete("/users/:id", (req, res) => {
  users = users.filter(u => u.id !== +req.params.id);
  res.status(204).end();
});

Step 4: HTTP Status Codes

Code	Meaning
200	OK
201	Created
400	Bad Request
404	Not Found
500	Server Error

FAQs

Express or Fastify?

Express is the standard with the biggest ecosystem. Fastify is faster and more modern. Start with Express.

How do I connect a database?

Use Mongoose for MongoDB or Prisma for SQL. More in our how-to guides.