How to create an API?

APIs (Application Programming Interfaces) allow different software applications to communicate with each other by calling functions and methods. Creating an API for your application enables other programs to access and work with your data and functionality.

This guide will walk through the basics of creating a simple REST API using Node.js and Express. We'll create routes to handle GET, POST, PUT, and DELETE requests.

What is Needed

To follow along, you'll need:

Set up the Server

First, create a new Node.js project. Open the terminal, make a project folder, initialize NPM, and install Express:

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

Next, create an index.js file and add the boilerplate Express code:

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

app.listen(3000, () => {
  console.log('Server listening on port 3000');
});

This will serve a basic Express app on port 3000.

Create API Routes

Now we can start adding routes and handlers for API requests. For example, to handle GET requests to the /users route:

app.get('/users', (req, res) => {
  res.json({user1: 'John', user2: 'Jane'}); 
});

The request handler callback function sends back a JSON response. Do the same for POST, PUT, and DELETE routes to handle those request types.

Use tools like Postman to test sending requests to your API endpoints. Make sure they return the proper status codes and data.

Final Touches

Some finishing touches for your API:

And that's the basics of getting an API up and running with Node.js and Express!