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UUID / GUID generator

Generate random version 4 UUIDs for identifiers, test data, database records, and development workflows. UUIDs are formatted identifiers, not secret tokens.

  • Updated: 2026-04-30
  • UUIDs are generated locally in your browser using cryptographically secure randomness when available.
Generated UUIDs will appear here.

UUID v4 Format

A version 4 UUID is a 128-bit identifier displayed as 36 characters, including hyphens. The version and variant bits are fixed by the standard, while the rest is random.

Use UUIDs for identifiers and test data. Do not treat them as private secrets.

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Privacy And Limitations

UUIDs are generated locally in your browser using cryptographically secure randomness when available.

  • UUIDs are identifiers, not secrets. Do not use them as passwords or authentication tokens.
  • Version 4 UUIDs are random and do not contain creation time or ordering information.
  • Use database constraints or application checks when uniqueness is critical.

Related Pages

FAQ

What is the difference between UUID and GUID?

In everyday development, GUID and UUID usually refer to the same 128-bit identifier format. GUID is common in Microsoft ecosystems; UUID is the standard term.

Can I use UUIDs as secrets?

No. UUIDs are designed as identifiers. For secret tokens, use longer random values and handle them with server-side security controls.

What does UUID v4 mean?

Version 4 means the UUID is randomly generated, with specific bits reserved to indicate version and variant.

Are UUID collisions possible?

In theory yes, but with proper random generation the probability is extremely low for normal application scales.

Should I use UUIDs as primary keys everywhere?

It depends on storage and indexing needs. UUIDs are great for distributed ID generation, but sequential IDs can still be preferable in some database workloads.