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Guide1 min readUpdated July 1, 2026

How to generate a UUID

Short answer

Use a UUID generator and copy the result — a 36-character identifier like 550e8400-e29b-41d4-a716-446655440000. Version 4 is random and the common default; version 7 is time-ordered and better as a database key.

What a UUID is

A UUID (universally unique identifier), also called a GUID, is a 128-bit value written as 32 hex digits in five hyphen-separated groups. It is designed to be unique without a central authority, so different systems can generate IDs that will not collide. See what is a UUID.

550e8400-e29b-41d4-a716-446655440000
UUID format (8-4-4-4-12)

Generate a UUID

  1. Pick a versionv4 (random) for general use; v7 (time-ordered) for DB keys.
  2. GenerateThe tool creates a fresh UUID instantly in your browser.
  3. Copy itUse it as a record ID, request ID, or file name.
Try it: UUID GeneratorGenerate UUIDs locally — nothing is uploaded.Open tool
v4 vs v7Version 4 is fully random and unpredictable. Version 7 embeds a timestamp so IDs sort roughly in creation order, which keeps database indexes efficient. For versions and their trade-offs, see the UUID versions reference.

When to use a UUID

  • Primary keys that can be generated on the client or offline
  • Request or trace IDs for logging and debugging
  • Unique file or object names without coordination
  • Merging records from multiple sources without key clashes

References

Questions

Are UUIDs guaranteed to be unique?

Not literally guaranteed, but the chance of two random v4 UUIDs colliding is astronomically small. For practical purposes they are treated as unique across systems.

What is the difference between a UUID and a GUID?

They are the same thing. GUID (globally unique identifier) is Microsoft's name for a UUID; the format and purpose are identical.

Does this send my data anywhere?

No. Utilumo's developer tools parse and transform input inside the browser tab. Nothing is uploaded, stored, or logged.

Keep reading

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