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UUID validator (version and variant)

Check that a UUID is valid and detect its version (v1/v3/v4/v5) and variant, in your browser.

🔒 100% client-side — no data sent

Check whether a UUID is valid and discover its version (v1, v3, v4 or v5) along with its variant. Validation runs 100% in your browser, with no data sent anywhere.

What is it for?

  • Confirm that an identifier received from an API is a valid UUID
  • Identify a UUID's version to understand how it was generated
  • Debug a UUID format rejected by a database
  • Validate identifiers before inserting them into a system

FAQ

How do I know a UUID's version?

The version is encoded in the first character of the third group. The tool detects it automatically (v1, v3, v4 or v5).

What is the difference between v4 and v1?

A v4 UUID is essentially random, whereas a v1 is based on a timestamp and the machine's MAC address.

What is a UUID's variant?

The variant indicates the bit layout and the standard followed. Most modern UUIDs use the RFC 4122 variant.