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Node.js

A JavaScript runtime for running JS outside the browser, on a server.

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Overview

Node.js runs JavaScript outside a browser using the same V8 engine Chrome uses, adding APIs for the file system, networking, and processes that browsers don't expose. It made JavaScript a viable full backend language, not just a frontend scripting tool.

What it is
A JavaScript runtime built on Chrome's V8 engine, for running JS on a server or in a CLI.
Why it's used
It lets a team use one language (JavaScript/TypeScript) across frontend and backend, with a huge package ecosystem (npm).
Where it fits
After JavaScript fundamentals -- Node.js is JavaScript plus server-side APIs, not a separate language. The Node.js and Express Backend Development course covers this in depth: the event loop, modules, async patterns, and building a real, tested, operationally-ready API, with guided local labs for the real server work this platform's browser sandbox can't execute.

Core concepts

  • The event loop
  • Modules (require/import)
  • The file system API
  • npm and package.json
  • Building an HTTP server

Example

http.createServer starts a raw HTTP server -- frameworks like Express build a more convenient API on top of exactly this primitive.

const http = require("node:http");
http.createServer((req, res) => {
  res.end("Hello from Node.js");
}).listen(3000);

Common use cases

  • Backend APIs and servers
  • Command-line tools
  • Build tooling (bundlers, task runners)

Project ideas

  • A minimal HTTP server that responds differently based on the request path

Official references