Build a REST API with Node.js and Express

Introduction

Node.js is a powerful runtime for building scalable server-side applications. In this guide, we will create a basic REST API that handles JSON data and utilizes middleware.

Step 1: Initialize the Project

First, create a new folder for your project and initialize it with a package.json file.

mkdir my-node-api
cd my-node-api
npm init -y

Step 2: Install Dependencies

We need express for the server framework and dotenv to manage our environment variables.

npm install express dotenv

Step 3: Create the Server

Create a file named index.js. This code sets up a basic server that listens on a specific port and returns a JSON response.

require('dotenv').config();
const express = require('express');
const app = express();
const PORT = process.env.PORT || 3000;

// Middleware to parse JSON
app.use(express.json());

// Basic Route
app.get('/api/status', (req, res) => {
  res.json({ 
    status: 'Online', 
    message: 'API is running successfully' 
  });
});

app.listen(PORT, () => {
  console.log(`Server is running on http://localhost:${PORT}`);
});

Step 4: Configure Environment Variables

Create a .env file in the same folder. This keeps your sensitive configurations separate from your logic.

PORT=5000
NODE_ENV=development

Step 5: Test the API

Run your server and use a tool like Postman or your browser to verify the output.

node index.js

You should see the JSON success message on your screen at http://localhost:5000/api/status.