Developer tools
UUID Generator
Generate one or many RFC 4122 v4 UUIDs (and nil UUIDs) in your browser.
UUIDs are generated locally via the Web Crypto API — none of them leave your browser.
How it works
- 1Pick how many UUIDs you need (1–1000).
- 2Choose between v4 (random) or the nil UUID.
- 3Click Generate and copy the result.
Use cases
- Seed database rows with unique IDs.
- Mock API responses while developing.
- Create idempotency keys for HTTP requests.
Frequently asked questions
Is this a real RFC 4122 v4 UUID?
Yes. The browser's Web Crypto API (crypto.randomUUID) is used; it follows RFC 4122 exactly.
Are the IDs cryptographically random?
Yes — they use the same CSPRNG that powers Web Crypto. Suitable for tokens, idempotency keys, and non-secret identifiers.
What is a "nil" UUID?
A special placeholder UUID consisting only of zeros: 00000000-0000-0000-0000-000000000000. Useful as a sentinel value.
Do you log generated UUIDs?
No. Generation happens entirely in your browser; nothing leaves the page.
Read the guide
How UUIDs work, and when to use which version
UUID v4 vs v7 vs ULID — when to use each, and why "random globally-unique ID" is more subtle than it looks.