Make one UUID or a thousand: random v4, time-ordered v7, ULID or NanoID, in upper or lower case, with or without hyphens. Paste a UUID to see its version and, for v1 and v7, when it was made.
| Kind | Looks like | Good for |
|---|---|---|
| UUID v4 | 3151cf9a-9957-4a83-9bc5-003ac0080e04 | the default: 122 random bits |
| UUID v7 | 019b76da-a800-7657-9e02-912618f01a95 | database keys: they sort by time, which keeps indexes fast |
| ULID | 01KDVDNA00C2P7QJSF3ZT1EVMR | like v7, in 26 letters and digits |
| NanoID | fk1mQX3LmsA1G6igcj_2_ | short ids in URLs |
The examples above were made when this page was built; the generator makes new ones every time. v7 and ULID start with the time in milliseconds, so ids made later sort after earlier ones.
Not in practice. A v4 UUID has 2¹²² possible values: you would need to make about a billion a second for 85 years before a clash became as likely as not. They come from your browser’s cryptographic random generator.
Nothing important: GUID is Microsoft’s name for a UUID. They have the same format.
For database primary keys, usually: v7 ids are made in time order, so new rows go to the end of the index. For tokens that shouldn’t reveal when they were made, use v4.
Yes. They use crypto.getRandomValues, the browser’s cryptographic random source, and are made on your device.
Open all 35 Dev Tools. Everything runs in your browser; nothing you paste is uploaded.