Cryptographically random version 4 UUIDs — generated in your browser, single or bulk
A Universally Unique Identifier is a 128-bit value written as 36 characters (32 hex digits + 4 hyphens). "GUID" is Microsoft's name for the same thing.
V4 UUIDs are generated from 122 random bits (6 bits are fixed to mark version and variant). This tool uses your browser's cryptographic random source, not a weak pseudo-random generator.
You'd need to generate about 2.7×1018 UUIDs to reach even a 50% chance of a single duplicate — generating a billion per second, that's 85 years.
Database primary keys, API request IDs, filenames, distributed systems — anywhere identifiers must be created independently on many machines without coordinating.
UUIDs are created by your browser's crypto API on your device. Nothing is requested from or logged by our server.
The third group always starts with 4 (version), and the fourth group starts with 8, 9, a or b (variant): xxxxxxxx-xxxx-4xxx-axxx-xxxxxxxxxxxx.