Question 1

Are these UUIDs cryptographically secure?

Accepted Answer

Yes. They are generated with the browser's Web Crypto API (crypto.randomUUID, backed by getRandomValues), which is a cryptographically secure random source — not Math.random. That makes them unguessable and safe for idempotency keys and request IDs.

Question 2

What version of UUID does this create?

Accepted Answer

Version 4 (random) UUIDs. The version digit is always 4 and the variant bits follow RFC 4122, so the identifiers are valid v4 UUIDs.

Question 3

What is the chance two UUIDs collide?

Accepted Answer

Astronomically small. A v4 UUID has 122 random bits, so you would need to generate billions per second for decades before reaching a 50% chance of a single collision.

Question 4

Can I generate UUIDs in bulk and reformat them?

Accepted Answer

Yes. Produce up to 100 at once, then toggle uppercase, remove hyphens, or wrap in braces. Copy them individually or copy the whole list with one button.

Question 5

Does it support UUID v1 or v7?

Accepted Answer

Currently only v4. v1 is timestamp-based and v7 is timestamp-prefixed and still emerging — both could be added later. For most modern use cases, v4 is the safe default.

Generate v4 UUIDs in bulk

Generated UUIDs