UUID Generator

A UUID (Universally Unique Identifier) is a 128-bit identifier shown as 36 characters, like 3f2504e0-4f89-11d3-9a0c-0305e82c3301. A randomly generated UUIDv4 is so unlikely to collide that you can use it as a unique ID in databases, APIs, and distributed systems without a central authority.

UUIDv4 is fully random and gives maximum unpredictability. UUIDv7 embeds the current timestamp in its first bits, so IDs sort chronologically — better for database index performance — while still containing random bits for uniqueness.

Yes. UUIDs are generated entirely in your browser using the Web Crypto API's cryptographically secure random number generator. Nothing is sent to our servers, and the same UUID is never shown to anyone else.

The nil UUID is 00000000-0000-0000-0000-000000000000 — a special value of all zeros. It is not random; systems use it as a sentinel meaning 'no value' or 'unknown', similar to null.

Practically, no. There are 2^122 possible v4 UUIDs — about 5.3 undecillion. Generating a billion UUIDs every second for 85 years would give you roughly a 50% chance of a single collision.