UUID Validator
Validate UUID format and identify its version and variant instantly.
The UUID Validator checks whether an identifier is a well-formed UUID and tells you which version it is: version 1 (time-based), version 4 (random), or the special nil and max UUIDs. It also reports the RFC 4122 variant from the format's reserved bits.
Format rules are stricter than they look: a UUID needs exact 8-4-4-4-12 hex grouping and the version nibble must match its position in the third group. A subtly wrong value — extra characters, a bad version nibble, or a mangled segment — fails validation, which is exactly the information you need when an id looks right but does not match anything in the database.
The tool checks multiple values at once when pasted one per line, and it runs entirely in your browser. Note that format validation does not prove the id exists anywhere — it confirms structure and version, not registration.
Paste a UUID to validate its format, version and variant.
How to use the UUID Validator
- Paste one UUID, or several (one per line).
- Each value gets its verdict: valid with version, or invalid.
- Read the RFC variant note for valid values.
- Check the special nil (all zeros) and max (all f's) handling.
- Copy nothing — this tool only reads.
Frequently asked questions
What do the UUID versions mean?
Version 1 encodes time and node (MAC) information, version 3 and 5 are deterministic hashes of a namespace and name (MD5 and SHA-1), version 4 is random. The validator reads the version nibble — the first character of the third group — and reports it.
What is the nil UUID?
00000000-0000-0000-0000-000000000000 — every bit zero. It is used as a sentinel meaning 'no value' in many systems and databases, and it validates as a special case rather than a version.
Does validation guarantee the UUID exists in my database?
No — it only confirms the string is structurally valid and identifies its version. Whether that id corresponds to a real record is a data question this tool cannot answer.
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