What is Node.js?
Node.js is an open-source, cross-platform JavaScript runtime environment that allows developers to run JavaScript on the server-side. It uses the V8 engine developed by Google for Chrome, enabling fast and efficient code execution outside the browser.
Node.js was created by Ryan Dahl in 2009. Its key innovation was using non-blocking, event-driven I/O to build scalable network applications. Since then, it has gained wide adoption in web development, especially for real-time applications like chat and APIs.
- Asynchronous and Event-Driven
- Very Fast (powered by Google V8 engine)
- Single-Threaded but Highly Scalable
- No Buffering — outputs data in chunks
- Cross-platform (Windows, Linux, macOS)
Node.js uses a single-threaded event loop model. Unlike traditional servers that spawn new threads for each request, Node.js handles many connections simultaneously using callbacks and non-blocking I/O, making it lightweight and efficient.
Traditional servers (like Apache) create a new thread for each request. Node.js, however, operates on a single-threaded event loop, using non-blocking I/O operations, which allows it to handle thousands of requests simultaneously with minimal resources.
To install Node.js:
- Go to the official website: https://nodejs.org
- Download the LTS version for your OS
- Run the installer and follow the instructions
- Verify with:
node -vandnpm -vin terminal
npm is the default package manager for Node.js. It allows you to install, manage, and publish Node.js packages. It has the largest software registry in the world with over 1 million packages.
Here’s a basic example of a Node.js web server:
const http = require('http');
const server = http.createServer((req, res) => {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello, Node.js!');
});
server.listen(3000, () => {
console.log('Server running at http://localhost:3000/');
});
- Real-time chat applications
- REST APIs and backend services
- Single-page applications (SPAs)
- Streaming services
- IoT applications
Node.js revolutionized backend development by enabling JavaScript to be used server-side. Its non-blocking, event-driven architecture makes it ideal for building scalable, high-performance applications across industries.


