UUID Generator
Generate cryptographically secure UUIDs — v4 and v7
About UUID Generator
A UUID (universally unique identifier) is a 128-bit value written as 32 hexadecimal digits in five groups, such as 123e4567-e89b-12d3-a456-426614174000. UUIDs let independent systems create identifiers without coordinating, with a negligible chance of collision.
This tool generates version 4 UUIDs, which are random, and version 7 UUIDs, which begin with a timestamp so that newly created values sort roughly in creation order. Random values come from the browser's cryptographically secure random number generator.
Common use cases
- Creating primary keys or correlation IDs for tests and seed data.
- Generating unique identifiers for records before they reach the database.
- Choosing v7 when you want index-friendly, time-ordered identifiers.
- Producing several IDs at once for fixtures or documentation.
Frequently asked questions
- Should I use v4 or v7?
- Use v4 when you only need uniqueness. Use v7 when IDs are database keys, since time-ordered values reduce index fragmentation compared with fully random ones.
- Can two UUIDs ever collide?
- In theory yes, but for random v4 values the probability is so small that it is ignored in practice.
- Are UUIDs secret?
- Do not treat them as secrets or access tokens. Use a dedicated random token for anything that grants access.