Kitloft

All tools / Security & identifiers

UUID generator

Generate random v4 or time-sortable v7 UUIDs, and inspect any UUID you already have.

UUIDs











Common questions


Should I use UUID v4 or v7?
Use v7 for database primary keys. It starts with a timestamp, so new rows are inserted at the end of the index instead of at random places, which keeps B-tree indexes fast. Use v4 when the ID should reveal nothing, not even when it was created.


Can two UUIDs collide?
In practice, no. A v4 UUID has 122 random bits; you would need to generate about a billion per second for 85 years to have a 50% chance of one collision.


Is UUID v7 a standard?
Yes. It was standardised in RFC 9562 in 2024, and PostgreSQL 18 has a built-in uuidv7() function.


Are these UUIDs secure?
They are made with the browser's cryptographically secure random generator. Even so, do not use UUIDs as secret tokens; use the password and secret generator for that.