UUID Generator

A UUID (Universally Unique Identifier) is a 128-bit value used to identify information without requiring a central authority to hand out IDs. It's written as 32 hex digits split into five groups by hyphens, e.g. 550e8400-e29b-41d4-a716-446655440000, and is commonly used for database primary keys, distributed systems, session tokens, and file or object identifiers.

This tool generates version 4 (v4) UUIDs, which are built from random or pseudo-random bits rather than being derived from a timestamp or hardware address. It uses the browser's built-in crypto.randomUUID() when available, falling back to a Math.random()-based generator that still follows the RFC 4122 v4 format.

A v4 UUID has 122 random bits, giving roughly 5.3 x 10^36 possible values. You'd need to generate billions of UUIDs per second for billions of years before the probability of a single collision became meaningful. It's not mathematically impossible, but for practical purposes the chance is negligible.

Auto-incrementing integers are simpler and slightly faster to index, but they reveal record counts and creation order, and they clash easily when merging data from multiple databases or offline clients. UUIDs are a better fit when IDs need to be generated independently across services, shouldn't be sequential or guessable, or need to be merged later without collisions.

No. Every UUID is generated entirely client-side in your browser using the Web Crypto API — nothing is sent to a server, logged, or stored, so it's safe to generate IDs you intend to keep private before you've used them.