03 / DEVELOPER
UUID Generator
Generate RFC 9562 v4 (random) and v7 (time-ordered, database-friendly) UUIDs in batches of up to 100, fully offline.
How to use
- 1Pick a version: v4 for purely random IDs, v7 for time-ordered IDs that sort by creation time.
- 2Set the count (1–100) and click Generate. Click Regenerate to get a fresh batch.
- 3Use Copy to grab all IDs at once. Each line is a complete UUID.
- 4All entropy comes from the browser's crypto.getRandomValues — no network calls.
Frequently asked questions
When should I use v7 instead of v4?
v7 embeds a 48-bit Unix-millisecond timestamp at the start of the ID, so values sort by creation time. That makes them excellent database primary keys (better B-tree locality than v4) while still being globally unique.
Are these RFC compliant?
Yes — v4 follows RFC 9562 §5.4, and v7 follows §5.7. Version and variant bits are set correctly so other libraries will accept them.
Could two devices generate the same v7 in the same millisecond?
Theoretically possible but vanishingly unlikely: each ID has 74 random bits per millisecond. Across a single device you'll never see a collision.
Do you store generated IDs?
No. Generation is purely client-side; nothing is recorded or transmitted.
Why no v1 / v6?
v1 leaks the MAC address; v6 isn't yet widely supported. v4 and v7 cover the vast majority of real-world needs and avoid both pitfalls.