Generate a random UUID

Return a version 4 UUID from the platform’s cryptographic generator.

JavaScriptNode.js & browsers Version 1.0.0 · MIT · .md

function uuid() { return crypto.randomUUID(); }

Usage

const key = uuid();
/^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/.test(key); // → true
key.length; // → 36

Lines marked → were executed in Node.js 22 and in headless Chromium, and each result was compared with the value shown. Lines marked e.g. are illustrative.

Know the limits

• crypto.randomUUID() returns an RFC 9562 version 4 UUID. In browsers it requires a secure context: HTTPS or localhost.
• The original built UUIDs from Math.random, which is not a cryptographic generator.
• As an idempotency key, create the UUID once per operation and store it with the operation: a new UUID on every retry defeats deduplication. Oveyon accepts Idempotency-Key values of 1–190 characters; see Build an idempotency key.

The function above is the code the usage lines run. It does not validate its arguments; add checks where it receives untrusted input.

Keep exploring

• Generate a random boolean — Return true or false with equal probability.
• Generate a random floating point number in given range — Scale Math.random into [min, max).
• Generate a random hex color — Return a #rrggbb color from 24 random bits.