Developer Reference

UUID Version Reference

Published September 8, 2026

How the common UUID versions are generated. For the full explanation, see What Is a UUID?.

Version How It’s Generated
v1 Based on a timestamp and the generating device’s MAC address
v3 Name-based, using an MD5 hash of a namespace and name
v4 Randomly generated
v5 Name-based, using a SHA-1 hash of a namespace and name

Use the UUID Generator

The UUID Generator generates random UUIDs instantly.

Try it yourself

UUID Generator

Try our UUID Generator →

Frequently Asked Questions

Which UUID version is most commonly used today?

Version 4 (random), since it doesn’t require any coordination and doesn’t leak identifying information like a MAC address.

Can two different UUIDs ever collide?

Theoretically yes, but the probability for v4 UUIDs is astronomically small, effectively negligible for practical purposes.

Explore More

Find the right tool, or browse Brekzy's other resources.