What Is Express.js

Express.js is a lightweight web framework for Node.js used to build web servers, APIs, and backend applications. It simplifies server-side development by providing tools for routing, middleware, request handling, and response management.

Without Express.js, developers would need to work directly with Node.js HTTP modules, which often requires more repetitive code and manual configuration.

Example of a basic Express.js server:

const express = require('express');

const app = express();

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

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

In this example:

• express() creates an application instance;
• app.get() defines a route;
• req represents the request object;
• res represents the response object;
• app.listen() starts the server.

Why Developers Use Express.js

Express.js is popular because it is simple, flexible, and works well for both small and large applications.

Developers commonly use Express.js for:

• REST APIs;
• Backend services;
• Full-stack web applications;
• Authentication systems;
• Real-time applications.

Express.js also integrates easily with databases, templating engines, and frontend frameworks.

Express.js and Node.js

Express.js runs on top of Node.js and extends its functionality with a cleaner and more organized development experience.

Node.js provides the runtime environment, while Express.js provides tools for handling routes, middleware, and server logic more efficiently.