Utilore

UUID Generator

Press the button and get identifiers you can paste straight into a database, a config or a test fixture. They are made in the page — no server hands you a number that someone else has already seen.

Generated by your browser from a cryptographic random source — nothing is requested from a server.

How to use

Good to know

What version 4 actually guarantees

A v4 UUID is 122 random bits plus six fixed ones that mark the version and variant. There is no counter, no MAC address, no timestamp — nothing about your machine leaks into it. The chance of two colliding is small enough that databases treat them as unique without checking.

Random, not merely arbitrary

The numbers come from crypto.getRandomValues, the same source browsers use for keys, not from Math.random. That distinction matters the moment an identifier is used in a link or a token: predictable «random» values can be guessed, and guessed identifiers are found.

Frequently asked questions

Are the identifiers generated on a server?

No. They are produced in your browser and never sent anywhere — nobody else has a copy of the list you just made.

Can two people get the same UUID?

In practice, no. With 122 random bits you would need to generate billions per second for decades before a collision became likely.

Is a UUID safe to use as a password or token?

As a secret, a v4 UUID is genuinely random, but it is stored and logged like any identifier. Use a proper token for authentication and a UUID for identity.

Which format should I choose?

Lower case without braces is the standard form and what most databases expect. Braces and capitals exist for Microsoft tooling that still prints them that way.

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