Frequently asked questions
Are the UUIDs generated privately?
Yes. They are created in your browser using a cryptographically secure random source, with nothing uploaded. It works offline once loaded.
What is the difference between v4 and v7?
Version 4 is completely random, which is the most common type. Version 7 starts with a timestamp, so the IDs sort in the order they were created, which is useful as database keys.
Are these safe to use as unique identifiers?
Yes. Random version 4 UUIDs have an astronomically small chance of collision, so they are widely used as unique keys.
Can I generate many at once?
Yes, up to 1000 at a time. You can format them in uppercase, without hyphens, or wrapped in braces, then copy or download the list.
What is the Nil UUID?
The Nil UUID is all zeros and is sometimes used as a placeholder or default empty value.