What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit value like 3f9c1b2e-8a41-4d6f-9c3a-7b2e1f4a5d60. Version 4 UUIDs are generated from random data, and the space is so large (2¹²²) that collisions are practically impossible — you can generate them anywhere, with no coordination, and they'll still be unique.
Common uses
Database primary keys, API request IDs, file names, session tokens, and order references. This tool uses your browser's native crypto.randomUUID() — the exact function developers use in production code.