UUID Generator

How this UUID generator works

This generates version 4 (random) UUIDs using your browser's crypto.getRandomValues(), a cryptographically secure random source — not Math.random(), which is not safe for anything requiring true unpredictability. Each UUID is generated locally; nothing is transmitted or logged anywhere.

Just how unique is a v4 UUID?

A v4 UUID has 122 random bits (6 bits are fixed to mark the version and variant). To have a 50% chance of any two colliding, you'd need to generate roughly 2.7 quintillion of them. For context, that's far more UUIDs than there are grains of sand on Earth. In practice, collision risk is not a realistic concern for this tool's use cases.

UUID versions and formats

v4 (random) is the most common general-purpose choice and what this tool generates. v1 encodes the creation timestamp and a node identifier, which can leak information about when and where it was generated — often undesirable. v7, a newer standard, is time-ordered like v1 but without the privacy downsides, and is increasingly preferred for database primary keys because sequential IDs are friendlier to index performance. If a system you're integrating with expects a specific version, check its docs before assuming v4 is fine.