UUID Generator
Generate UUID v4 and v7 identifiers in bulk, plus ULIDs and nano IDs.
Runs in your browser
Generators
Which should I use?
- UUID v4
- 122 bits of randomness. The safe default when you need an identifier nobody can guess. Poor as a clustered primary key — random inserts fragment the B-tree.
- UUID v7
- A 48-bit millisecond timestamp followed by randomness, so values sort chronologically. This is what you want for database keys — sequential inserts, and you can read the creation time out of the ID.
- ULID
- Same idea as v7 but Crockford Base32 encoded — 26 characters, case-insensitive, and free of the characters people confuse when reading aloud.
- Nano ID
- 21 URL-safe characters, comparable collision resistance to UUID v4, and far shorter. Good for public-facing identifiers in URLs.