UUID Generator
Version 4 UUIDs from crypto-grade randomness — one for a quick ID, a hundred for seeding a table.
Generated on your device — never transmitted or logged.
Anatomy of a v4 UUID
xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx — the 4 marks the
version; the y position is always 8, 9, a, or b (the variant bits). The other 122 bits are pure randomness,
which is where the uniqueness comes from. If a generator gives you UUIDs without a 4 in that slot, it's
not generating valid v4s.
Common questions
What is a UUID?
A Universally Unique Identifier — a 128-bit value like f47ac10b-58cc-4372-a567-0e02b2c3d479 used as an ID that's effectively guaranteed unique without any central registry. Databases, APIs, and distributed systems run on them.
What does "version 4" mean?
V4 UUIDs are generated from random numbers (122 random bits). Other versions derive from timestamps or names; v4 is the default choice for "just give me a unique ID."
Can two v4 UUIDs ever collide?
Mathematically possible, practically never: you'd need to generate about 2.7 quintillion UUIDs to reach even a 50% chance of one duplicate. Your database will fail in a thousand other ways first.
Are these generated securely?
They use crypto.getRandomValues — your browser's cryptographic randomness — and are generated entirely on your device, never transmitted or logged.