Globally Unique Identifier (GUID)

GUID (or UUID) is an acronym for ‘Globally Unique Identifier’ (or ‘Universally Unique Identifier’). It is a 128-bit number used to identify information in computer systems. The term GUID is generally used by developers working with Microsoft technologies, while UUID is used everywhere else. When generated according to the standard methods, GUIDs are for practical purposes unique, without depending for their uniqueness on a central registration authority or coordination between the parties generating them, unlike most other numbering schemes. While the probability that a UUID will be duplicated is not zero, it is close enough to zero to be negligible.