Web Crypto API • Copy once, once gone
One-Shot UUID Generator
Exactly one UUIDv4 per page. The moment you copy it, it is spent and swapped for a fresh one — so you can never accidentally reuse the same identifier twice.
Click the UUID or the button to copy. On a successful copy it is spent and instantly replaced.
Recently spent
Nothing spent yet — your first copied UUID shows up here as a backup.
CSPRNG entropy, strictly local
Every UUID comes from crypto.randomUUID() backed by your browser’s CSPRNG (Web Crypto API). No server storage, no logging, no network round-trip — not even the first one.