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UUID Generator

Generate cryptographically random UUID v4 or time-ordered UUID v7 identifiers in bulk.

UUID v4 vs v7

A UUID is a 128-bit identifier written as 36 characters, e.g. 3f2b8c1e-9a4d-4e7b-b1c2-5d6e7f8a9b0c. You can generate them anywhere without coordinating with a central server, which makes them ideal for distributed systems, offline clients and public IDs that shouldn't reveal record counts.

  • v4 is 122 random bits. Collisions are astronomically unlikely, but random values scatter across database indexes, which can slow inserts in large B-tree tables.
  • v7 (RFC 9562, 2024) starts with a 48-bit millisecond Unix timestamp followed by random bits. IDs sort roughly by creation time, giving much better index locality while staying globally unique.

All values here come from crypto.getRandomValues, the browser's cryptographically secure random generator. Nothing is sent to a server.

When not to use UUIDs

Don't treat a UUID as a secret or a security token. Use a dedicated random token generator for password-reset links or API keys.