APIs are the backbone of contemporary online applications, providing smooth communication between the frontend and backend.
In this post, we'll step through constructing a basic REST API using Node.js & Express from scratch. Let’s get started! 🚀
📌 Step 1: Setup Your Node.js Project
First, verify you have Node.js installed. Then, initialize a new project:
sh Copy Edit mkdir simple-api && cd simple-api npm init -y
This produces a package.json file, which maintains dependencies.
📌 Step 2: Install Express.js
Express is a lightweight and quick framework for creating web applications in Node.js. Install it:
sh Copy Edit npm install express 📌 Step 3: Create Your Server
Create a new file server.js and add this code:
javascript Copy Edit const express = require('express'); const app = express(); const PORT = 3000;
app.get('/', (req, res) => { res.send('Hello, API! 🚀'); });
app.listen(PORT, () => { console.log(Server is operating on http://localhost:${PORT}); });
What’s Happening?
✔ express() initializes an Express app.
✔ app.get('/') handles GET queries to the root URL.
✔ app.listen(PORT) launches the server.
Run it with:
sh
Copy Edit node server. js
Visit http://localhost:3000 in your browser—you should see "Hello, API! 🚀".
📌 Step 4: Add More Routes
Let’s build routes to handle CRUD actions (Create, Read, Update, Delete). Modify server. js:
javascript Copy Edit app.use(express.json()); // Middleware to parse JSON
const users = [{ id: 1, name: 'John Doe' }] ;
// Get all users app. get('/users', (req, res) => { res.json(users); });
// Add a new user app. post('/users', (req, res) => { const newUser = { id: users.length + 1, ...req.body }; users.push(newUser); res.status(201).json(newUser); });
Now you can:
✔ GET /users → Retrieve all users
✔ POST /users → Add a new user
Test with Postman or cURL:
sh Copy Edit curl -X POST -H "Content-Type: application/json" -d '{"name": "Jane Doe"}' http://localhost:3000/users 📌 Step 5: Handling Errors
Let’s add error handling to enhance our API:
javascript Copy Edit app.use((req, res) => { res.status(404).json({ message: 'Route not found!' }); });
Now, if a user accesses an incorrect endpoint, they receive a 404 error instead of a blank answer.
📌 Step 6: Running and Testing 1️⃣ Start the server:
sh Copy Edit node server. js
2️⃣ Open http://localhost:3000/users in your browser or Postman to test.
3️⃣ Use Postman to submit a POST request to /users.
🚀 Next Steps 🔹 Add MongoDB with Mongoose for data storage. 🔹 Implement JWT authentication for security. 🔹 Deploy the API using Render, Vercel, or Heroku.
By following these instructions, you’ve constructed a completely functioning REST API using Node.js & Express! 🎉
💬 Have questions? Drop them in the comments!
#NodeJS #ExpressJS #RESTAPI #Backend #WebDevelopment
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