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UUID Generator (v4)

Generate cryptographically secure UUID v4 values in bulk using the Web Crypto API. Client-side only.

Click Generate to create cryptographically secure UUID v4 values, in bulk if you need them.

Generated UUIDs

What this UUID generator does

Generate random UUID v4 values using the Web Crypto API — the same source of randomness your browser uses for secure operations. No server, no seed, nothing stored. Generate one ID or thousands, with or without hyphens, in any case.

Why version 4

Version 4 UUIDs are fully random (122 bits of entropy). They are the standard choice when you need a unique identifier with no ordering or host information.
Uniqueness. Random UUIDs are not guaranteed unique in the mathematical sense, but the odds of a collision are negligible — billions of billions of IDs are needed before it becomes a realistic risk.
Format. A v4 UUID looks like xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, where y is one of 8, 9, a or b. The 4 and y are the markers that identify it as version 4.

Frequently asked questions

How do I generate a UUID v4?

Click Generate. Values are created with the Web Crypto API, which is cryptographically secure.

Can I generate many UUIDs at once?

Yes. Set the number of values and generate them in bulk, then copy the whole list at once.

Are generated UUIDs truly random?

Yes. Generation uses the browser's cryptographically secure random source — no predictable patterns or seeds.

Does UUID Generator (v4) upload my data?

No. UUID Generator (v4) runs entirely in your browser — your input never leaves this page.

Is UUID Generator (v4) free to use?

Yes. UUID Generator (v4) is completely free, with no account and nothing to sign up for.

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Updated 2026-08-07 · Runs in your browser — your data never leaves this page.