UUID Validator
UUID Validator checks whether a string is a syntactically valid UUID and, if it is, reports its version and variant along with the canonical form. It accepts hyphenated and unhyphenated input, braces and the urn:uuid: prefix.
Use it to confirm an identifier is well-formed before storing it or passing it to an API.
How to use UUID Validator
- 1
Paste a UUID
Enter the string you want to check.
- 2
Read the verdict
A clear valid or invalid result appears instantly.
- 3
Inspect the details
For valid UUIDs, see the version, variant and canonical form.
What makes a UUID valid
A UUID is a 128-bit value written as 32 hexadecimal digits, conventionally grouped 8-4-4-4-12 with hyphens. Any value matching that pattern is structurally valid.
This validator is lenient about formatting — it accepts uppercase, missing hyphens, surrounding braces and the urn:uuid: prefix — but it always shows you the canonical lowercase hyphenated form.
Version and variant
The version digit indicates how the UUID was generated: 4 for random, 1, 6 and 7 for time-based, 3 and 5 for name-based hashing, and 8 for custom layouts. The variant bits identify the UUID layout, which for almost all modern UUIDs is the RFC 4122 / DCE 1.1 variant.
Knowing the version helps you decide what a UUID can tell you — for instance, only versions 1, 6 and 7 embed a timestamp you can decode.
Frequently asked questions
- Does it accept UUIDs without hyphens?
- Yes. Unhyphenated input, braces and the urn:uuid: prefix are all accepted, and the canonical form is shown.
- Does a valid format mean the UUID is genuine?
- It means the string is well-formed. Validity here is about structure, not about whether the UUID actually identifies anything.
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