Building A Rest API with NodeJS and ExpressJS | Beginners Tutorial

NodeJS and ExpressJS are two popular technologies that are widely used for building web applications. In this tutorial, we will explore how to create a Rest API using these two frameworks.

Prerequisites

• Basic knowledge of JavaScript
• NodeJS and NPM installed on your machine

Step 1: Setting up the Project

First, we need to set up a new NodeJS project. Open your terminal or command prompt and run the following command:

mkdir rest-api
cd rest-api
npm init

Follow the prompts and fill in the necessary details for your project.

Step 2: Installing Dependencies

We will be using ExpressJS, a minimalistic web application framework for NodeJS. To install ExpressJS, run the following command:

npm install express

Step 3: Creating the API

Create a new file called index.js and open it in your code editor. This will be the entry point of our application.

const express = require('express');
const app = express();
const port = 3000;

app.get('/', (req, res) => {
  res.send('Hello World!');
});

app.listen(port, () => {
  console.log(`Server running on port ${port}`);
});

Step 4: Starting the Server

To start the server, simply run the following command in your terminal:

node index.js

You should see a message indicating that the server is running on port 3000.

Step 5: Testing the API

Open your browser and navigate to http://localhost:3000. You should see the message “Hello World!” displayed in your browser, indicating that the API is working correctly.

Step 6: Adding Routes

Now let’s add some routes to our API. Modify the index.js file as follows:

app.get('/api', (req, res) => {
  res.json({
    message: 'Welcome to our API!'
  });
});

app.post('/api/users', (req, res) => {
  // Handle user creation logic here
});

app.put('/api/users/:id', (req, res) => {
  // Handle user update logic here
});

app.delete('/api/users/:id', (req, res) => {
  // Handle user deletion logic here
});

Step 7: Testing the Routes

You can now test the routes using a tool like Postman or by sending HTTP requests using JavaScript. For example, to test the GET route, send a GET request to http://localhost:3000/api. You should receive a JSON response with the message “Welcome to our API!”.

Conclusion

Congratulations! You have successfully built a basic Rest API using NodeJS and ExpressJS. This tutorial covered the essential steps to set up a project, install dependencies, create routes, and test the API. From here, you can continue to expand and enhance your API based on your specific requirements.