Node.js ships with dozens of built-in modules — no npm install needed, just require() them by name. This lesson is a map of the ones worth knowing exist before the next few lessons cover the most-used ones properly.
| Module | What it's for |
|---|---|
fs | Reading and writing files |
path | Building and parsing file paths safely across operating systems |
os | Information about the computer Node is running on |
http | Creating web servers and making HTTP requests |
events | The EventEmitter class most of Node's async APIs are built on |
crypto | Hashing, encryption, and generating random values |
url | Parsing and building URLs |
util | Small helper functions used throughout Node itself |
Every built-in module is documented on nodejs.org/api — that page is the authoritative reference for exactly what each one can do; nothing here tries to replace it.
The node: prefix
Newer Node versions prefix built-in modules with node:, e.g. require('node:fs'). It's optional but makes it instantly clear, when reading someone else's code, that a name refers to a built-in module rather than an installed package.
The next four lessons work through fs, path/os, and then http — the module that turns everything so far into an actual running server.