UUID Validator

Check whether a string is a valid UUID and identify its version (v1, v4, v5, etc.). Paste a UUID with or without hyphens and click Run to inspect it.

  • Runs entirely in your browser
  • No data stored or sent to a server
  • Free forever — no signup
  • Instant conversion

Input and Output

Use the interactive encoder and decoder on this page to process your text.

Learn more about UUID validation

How to Validate and Inspect UUIDs

UUID Validation

When to Validate UUIDs

Validate UUIDs when debugging API payloads, checking config files, verifying database imports, or confirming that an ID string matches expected format before using it in queries or comparisons.

Real-World Examples

Confirm a webhook payload ID is valid before querying by primary key

Detect whether an ID is v4 (random) vs v1 (time-based) for migration debugging

Normalize hyphen-less UUIDs from legacy systems: 550e8400e29b41d4a716446655440000

Common Mistakes

  • Confusing UUIDs with MongoDB ObjectIds (24 hex chars, no hyphens)
  • Checking length only without validating version and variant bits
  • Treating invalid hex characters as valid after partial truncation

Edge Cases

  • Nil UUID 00000000-0000-0000-0000-000000000000 is syntactically valid but often semantically special
  • Version nibble 0 or missing variant bits may indicate non-standard or corrupted IDs
  • UUIDs with surrounding whitespace or braces need trimming before validation

Developer Tips

  • Compare UUIDs case-insensitively — hex digits a–f and A–F are equivalent
  • Use native validators in your language (e.g. Python uuid.UUID) in production code
  • Log the version when debugging mixed ID schemes in legacy databases

Frequently asked questions

Does this accept UUIDs without hyphens?

Yes. The validator accepts both standard hyphenated format and 32-character hex strings without hyphens, normalizing output to the standard form.

How is the UUID version detected?

The version is read from the first hex digit of the third group (the M in xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx). Values 1–8 map to known RFC versions.

What does the variant field mean?

The variant bits in the fourth group indicate which UUID specification applies. RFC 4122 variant IDs have N values of 8, 9, a, or b.