About the UUID Generator
A UUID is a 128-bit identifier that is unique without a central authority, which makes it the standard choice for database primary keys, distributed system identifiers and idempotency keys. This tool generates them using the browser's secure random source. Version 4 is fully random and the most common; version 7, newer, encodes a timestamp in the high bits so the values sort in creation order, which improves database index locality.
You can generate up to 500 at once, in upper or lower case, with or without hyphens, and optionally wrapped in braces for formats such as Microsoft GUIDs. The nil UUID (all zeros) is available as a placeholder value. Everything runs locally, so the identifiers are yours alone.
For shorter unique IDs, the Nano ID and ULID generators offer compact, URL-safe alternatives.
How to use
- Choose the version and how many to generate.
- Set formatting: case, hyphens, braces.
- Copy or download the UUIDs.
Common questions
- v4 or v7?
- v4 is random and ubiquitous. v7 embeds a timestamp so IDs sort by creation time, which helps database index performance. Use v7 for new primary keys if your stack supports it.
- Are these collision-safe?
- v4 has 122 random bits; the chance of a collision is negligible for any realistic volume.
- Is the randomness secure?
- Yes, it uses the browser's cryptographic random source.
- What is the nil UUID for?
- It is all zeros, used as a placeholder or "no value" marker.