How this UUID generator works
Every identifier here is a version 4 UUID built from your browser’s cryptographically secure random number generator (crypto.getRandomValues). The tool takes 16 random bytes, stamps the version nibble to 4 and the variant bits to the RFC 4122 pattern, and formats the result as the familiar 8-4-4-4-12 hex string. That is exactly what libraries like Python’s uuid4() or PostgreSQL’s gen_random_uuid() do — nothing is derived from your machine, the time, or a server, and nothing leaves your browser.
Need identifiers for a seed script or test fixtures? Set the count up to 100 and you get one UUID per line, ready to paste. The uppercase and no-hyphen options cover systems that store UUIDs as plain 32-digit hex. For a deeper look at versions and collision math, see our guide What Is a UUID?
When to reach for a UUID
- Primary keys in distributed databases, where no single sequence exists.
- Correlation and request IDs in logs and traces across services.
- Filenames and object-storage keys that must never clash.
- Idempotency keys for payment and API retries.
UUIDs are unique, not secret
A v4 UUID is unguessable enough for most identifiers, but it is not a credential: it has 122 bits of randomness with a fixed, recognizable format, and it often ends up in URLs and logs. For anything meant to authenticate a user, generate a proper secret with the Password Generator instead.