UUID Generator
Generate cryptographically random UUID v4 identifiers in bulk.
UUID v4
Private by design. UUIDs are generated locally with the Web Crypto API. Nothing is transmitted or recorded.
Frequently asked questions
What is a UUID v4?
A 128-bit identifier where 122 bits are randomly generated. It requires no central coordination, which makes it useful for IDs created independently on many machines.
Are these UUIDs safe to use in production?
Yes. They come from the Web Crypto API, which is a cryptographically secure random source, so the values are not predictable.
Can two UUIDs ever collide?
In theory yes, in practice no. Generating a billion UUIDs per second for a century still leaves the chance of a single collision negligible.
Should I use a UUID as a database primary key?
It works, but random UUIDs fragment B-tree indexes because inserts land in random positions. For high insert volumes consider UUID v7 or a sortable ID scheme instead.
About the UUID Generator
A version 4 UUID is 128 bits, of which 122 are random and 6 are fixed version and variant markers. It is written as 32 hexadecimal digits in a 8-4-4-4-12 pattern.
Randomness comes from crypto.getRandomValues, the same cryptographically secure source used for key material, not from Math.random. The collision probability is small enough to ignore: you would need on the order of 10^18 identifiers before a duplicate becomes likely.
Use the no-hyphen option for compact database columns and the uppercase option when matching a Microsoft-style GUID format.