Core Modules Overview

6 min read

Core Modules Overview

Node.js ships with a rich set of built-in (core) modules — no npm install required. They cover file system access, HTTP networking, streams, cryptography, OS information, path manipulation, and more. You load them with require("moduleName") or import.

fs — read, write, watch files and directories
path — join, resolve, parse file paths cross-platform
http / https — create HTTP(S) servers and make requests
os — CPU count, total memory, hostname, platform
events — EventEmitter class for pub/sub patterns
stream — readable, writable, and transform streams
crypto — hashing, encryption, random bytes
url — parse and format URLs
process — environment variables, argv, exit codes
child_process — spawn subprocesses and shell commands

In Node.js v14+ you can prefix core modules with node: (e.g. import fs from "node:fs") to make it explicit that you are importing a built-in, not an npm package.

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