What Is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit identifier that is guaranteed to be unique across space and time. UUIDs are commonly used in software development as database primary keys, session tokens, and distributed system identifiers.

UUID v4 Format

This tool generates version 4 UUIDs, which are randomly generated. The format is:

xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx

Where x is a random hexadecimal digit and y is one of 8, 9, a, or b. The 4 indicates version 4.

Common Use Cases

Database IDs: Primary keys that don't require sequential numbering.
API tokens: Unique identifiers for sessions and requests.
File naming: Collision-free filenames for uploads.
Distributed systems: IDs generated independently across nodes.

Frequently Asked Questions

How unique are UUID v4s?

With 122 random bits, the probability of generating a duplicate is astronomically low. You would need to generate about 2.71 quintillion UUIDs to have a 50% chance of a collision.

Are these UUIDs cryptographically secure?

Yes. This tool uses crypto.getRandomValues(), which provides cryptographically secure random numbers.