How to Generate UUID in JavaScript

How to Generate a UUID in JavaScript

The simplest way to generate a UUID in JavaScript is crypto.randomUUID(), built into every modern browser (Chrome 92+, Firefox 95+, Safari 15.4+) and Node.js (available globally on Node 19+, or via require('crypto') on Node 14.17+/16.7+) with zero dependencies. The c++ uuid reference explains how to generate and parse UUIDs in C++ with proper formatting.

app.js (browser or Node.js 19+)

const myUuid = crypto.randomUUID();
console.log(myUuid);
// Output: 550e8400-e29b-41d4-a716-446655440000

server.js (older Node.js)

const { randomUUID } = require('crypto');

const myUuid = randomUUID();
console.log(myUuid);
// Output: 550e8400-e29b-41d4-a716-446655440000

Explanation

crypto.randomUUID() is available as a global in browsers and on Node.js 19+, so no import is needed in those environments.
On Node.js 14.17+/16.7+, before it became a global, require('crypto').randomUUID() gives you the exact same function.
It returns a random, RFC 4122 version 4 UUID as a plain 36-character string — not an object — so it drops straight into JSON, URLs, or template literals.
Under the hood it draws from the platform's cryptographically secure random number generator (the Web Crypto API in browsers, Node's crypto module on the server).

Convert a String to a UUID in JavaScript

JavaScript has no dedicated UUID type — a UUID is just a string — so "converting" one really means validating that a string is well-formed before you trust it. See the python uuid generator page for UUID validation regex, error handling, and framework-specific integration examples.

app.js

function isValidUUID(str) {
  const regex = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i;
  return regex.test(str);
}

console.log(isValidUUID('550e8400-e29b-41d4-a716-446655440000')); // true
console.log(isValidUUID('not-a-uuid')); // false

app.js (uuid package)

import { validate, version } from 'uuid';

const str = '550e8400-e29b-41d4-a716-446655440000';
console.log(validate(str)); // true
console.log(version(str)); // 4

Explanation

Since a UUID is just a string in JavaScript, isValidUUID() uses a regex to check the 8-4-4-4-12 hexadecimal pattern.
The i flag makes the regex case-insensitive, so it matches both uppercase and lowercase hex digits.
The uuid package's validate() function checks the same shape but is RFC-aware, and version() reports which UUID version the string encodes.
Always validate UUIDs coming from user input, URL parameters, or API requests before using them in database queries.

Other Options for Generating UUIDs in JavaScript

crypto.randomUUID() only produces version 4 UUIDs, so reach for the uuid npm package when you need version 1, 5, or 7 identifiers, or support for older browsers and Node.js versions where the native API isn't available.

Terminal

npm install uuid

app.js

import { v4 as uuidv4, v7 as uuidv7 } from 'uuid';

// Version 4 - random, same style as crypto.randomUUID()
const randomId = uuidv4();

// Version 7 - Unix timestamp + random, sortable and index-friendly
const sortableId = uuidv7();

Explanation

npm install uuid adds the package to your project; it works in Node.js and in bundled browser code alike.
v4() produces the same style of random UUID as crypto.randomUUID(), useful as a drop-in for environments where the native API isn't available.
v7() encodes the current Unix millisecond timestamp in the most significant bits, producing IDs that sort chronologically — ideal for database primary keys.
The package also exports v1() (timestamp + node ID) and v5()/v3() (deterministic, namespace-based) for cases crypto.randomUUID() can't cover.

Generate UUID in JavaScript

How to Generate a UUID in JavaScript

Explanation

Convert a String to a UUID in JavaScript

Explanation

Other Options for Generating UUIDs in JavaScript

Explanation

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