UUID & ULID Generator

How to use this tool

1. Pick how many (1–20) and which kind.
2. Press Generate. Each identifier is on its own line.
3. Copy the list into your data, code or test fixtures.

Worked example

With the sample (5 UUIDs), each line looks like xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx — 32 hex digits in five groups, with a 4 marking version 4 and the next group starting with 8, 9, a or b marking the variant. ULIDs instead look like 26 characters starting with a timestamp portion (for example, a ULID generated now starts with characters encoding the current millisecond time), followed by random characters — which is why ULIDs sort in the order they were created and UUIDs v4 do not.

What this tool does not do / Limits

Identifiers are random, not secret: do not use a UUID or ULID as a password, an access token, or the sole protection for private data. Randomness comes from the browser's cryptographic generator; if it is unavailable, the tool reports an error rather than falling back to a weaker guessable generator. ULID timestamps expose the creation time in the identifier itself — avoid ULIDs where that timing is sensitive.

Frequently asked questions