UUID Generator
Generate one or many RFC 4122 version-4 UUIDs in the browser with crypto.randomUUID — uppercase or lowercase, with or without hyphens, copy each or all at once.
What is it
A UUID is a 128-bit identifier designed so that two random generations almost never collide. Version 4 fills the bits with random data, which is why it is the default ID for database keys, API tokens, session ids and test fixtures. This page generates real cryptographically random UUIDs right in your browser — no server involved.
Notes & fun facts
The chance of a collision in UUID v4 is famously tiny: you would have to generate a trillion UUIDs before the odds of one repeat become about 50/50. That is why engineers quietly trust them for distributed systems where two machines must never pick the same id without phoning each other.
Origin & history
UUIDs were first standardised in ISO/IEC 11578:1996, and then in RFC 4122 (July 2005) by a working group led by Paul Leach, which defined the four versions — version 4 is the purely random one. Browsers expose it today as crypto.randomUUID().