Node.js Introduction

Last Updated : 11 May, 2026

Node.js is a runtime environment that allows JavaScript to run outside the browser for building server-side applications.

  • Built on the V8 JavaScript engine.
  • Supports asynchronous, event-driven programming.
  • Efficient for scalable network applications.
Nodejs
Nodejs

"Hello, World!" Program in Node.js

A “Hello, World!” program is the simplest way to begin with Node.js, showing how JavaScript runs outside the browser.

  • Executes JavaScript in a server or command-line environment.
  • Does not rely on a browser console.
JavaScript
console.log("Hello, World!");

Output:

helloworld
Hello, World! in NodeJS

Working of Node.js

Node.js is a runtime environment that enables JavaScript to run outside the browser for building scalable server-side applications.

  • Built on the V8 JavaScript engine.
  • Uses asynchronous, event-driven architecture.
  • Suitable for scalable network applications.

Components of Node.js Architecture

Node.js architecture consists of components that work together to handle asynchronous, non-blocking operations efficiently.

  • V8 Engine: Compiles JavaScript to machine code for fast execution.
  • Event Loop: Manages asynchronous tasks without blocking the main thread.
  • Libuv: Handles I/O operations, thread pool, and timers.
  • Non-Blocking I/O: Executes tasks without waiting for previous ones to complete.
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