UUIDTools.com

Version 8 UUID Generator

Custom/vendor-specific layout; only version and variant bits are fixed.

Decode
Options & format

Formatting is applied instantly in your browser. A GUID is a UUID: tick Uppercase + Braces for the Microsoft registry style.

API
http://uuidtools.com/api/generate/v8

Plain-text and JSON API docs: no key required.

About Version 8 UUIDs

Version 8 is the experimental/vendor-specific UUID. RFC 9562 fixes only the 4 version bits and 2 variant bits; the remaining 122 bits are yours to define, for example to embed a shard ID, a SHA-256 name hash, or a custom timestamp.

Our generator fills the free bits with random data to show the format. Build your own layout in code and use the decoder to check that the version and variant are correct.

Structure

custom_a (48) | 8 | custom_b (12) | variant (2) + custom_c (62)

When to use it

  • You need a UUID-shaped ID with application-specific structure and no collision with other versions.

When to avoid it

  • Interchange with other systems: nobody else can interpret your layout.

Frequently asked questions

Can I use SHA-256 for name-based UUIDs?

RFC 9562 suggests v8 for this: hash with SHA-256, keep the first 128 bits and then overwrite the version and variant bits.