Kastavo

UUID Validator

Paste a UUID and see whether the format is valid and which version it uses.

How it works

A valid UUID has 32 hexadecimal digits in 5 groups (8-4-4-4-12), with two nibbles fixed by the specification: the first digit of the third group indicates the version (1 to 5), and the first digit of the fourth group indicates the RFC 4122 variant (always 8, 9, a, or b). This validator checks that structure and, when valid, reports the detected version: v1 is based on a timestamp and network address; v3 and v5 are generated from a namespace and a name, using MD5 (v3) or SHA-1 (v5); v4 is generated almost entirely from random numbers, and is the most common version today.

Frequently asked questions

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