Building a REST API

Design and implement a REST API: pick correct status codes, model resources around URLs, support CRUD, and enable CORS for browser clients.

RESTAPIHTTPstatus codesCORS

Duration

⏱ About 2.5 hours

Level

📊 Intermediate

Prerequisite

🎯 node-04

OUTCOME

A working /tasks REST API with full CRUD and proper status codes

What you'll learn

1Design resource-based URLs
2Return the right status code for each scenario
3Implement create / read / update / delete
4Enable CORS for cross-origin browser requests

1. REST Conventions

Method	URL	Action	Success Status
GET	/tasks	List all tasks	200
GET	/tasks/:id	Get one task	200 (or 404)
POST	/tasks	Create a task	201
PUT	/tasks/:id	Replace a task	200
PATCH	/tasks/:id	Partial update	200
DELETE	/tasks/:id	Delete a task	204 (no body)

2. Sample CRUD

javascript

import express from "express";
import cors from "cors";

const app = express();
app.use(cors());
app.use(express.json());

let tasks = [];
let nextId = 1;

app.get("/tasks", (req, res) => res.json(tasks));
app.get("/tasks/:id", (req, res) => {
  const t = tasks.find(t => t.id == req.params.id);
  if (!t) return res.status(404).json({ error: "Not found" });
  res.json(t);
});
app.post("/tasks", (req, res) => {
  const task = { id: nextId++, title: req.body.title, done: false };
  tasks.push(task);
  res.status(201).json(task);
});
app.delete("/tasks/:id", (req, res) => {
  tasks = tasks.filter(t => t.id != req.params.id);
  res.status(204).end();
});

app.listen(3000);

3. Status Codes Cheat Sheet

2xx — success (200 OK, 201 Created, 204 No Content)
3xx — redirection (301 Moved, 304 Not Modified)
4xx — client error (400 Bad Request, 401 Unauthorized, 403 Forbidden, 404 Not Found, 409 Conflict)
5xx — server error (500 Internal Server Error, 503 Service Unavailable)

4. CORS

Browsers block cross-origin requests by default. Enable CORS so your frontend can call your API.

javascript

import cors from "cors";
// Allow specific origins
app.use(cors({
  origin: ["http://localhost:5173", "https://myapp.com"],
  credentials: true,
}));

Example code / lecture materials

All lecture materials and example code are openly available on GitHub.

View on GitHub ↗