A Universally Unique Identifier (UUID) is a 128-bit label used for information in computer systems. The term Globally Unique Identifier (GUID) is also used, typically in software created by Microsoft.

When generated according to standard methods, UUIDs are, for practical purposes, unique. Their uniqueness does not depend on a central registration authority or coordination between generating parties, unlike most other numbering schemes.

This tool generates Version 4 UUIDs, which are created using random or pseudo-random numbers.