Glossary · Semantic interoperability and information models
Globally unique identifier (GUID)
Also known as: GUID, Universally unique identifier (UUID), UUID
German: Global eindeutiger Identifikator (GUID)
In information technology, a globally unique identifier (GUID) is a 128-bit value generated so that it is unique in practice without a central registry, usually written as 32 hexadecimal digits in five groups. GUID is the Microsoft term for what ISO/IEC 9834-8 and RFC 9562 standardize as a universally unique identifier (UUID).
- Information models
- Standards
In one sentence
A GUID is a 128-bit identifier, also called UUID, that is unique in practice without a central registry.
Example
Each project object in the engineering tool gets a GUID such as 3f2504e0-4f89-11d3-9a0c-0305e82c3301, so it can be tracked even when renamed.
How it applies
- Engineering: GUIDs let tools and systems create identifiers independently without collisions, for example for objects in engineering projects, database records or OPC UA nodes with GUID identifiers.
- Integration: Keep a GUID stable over the life of the object, even when names or locations change; this is what makes it useful for synchronization and traceability.
- Documentation: Content management systems use GUIDs for topics and resources. When content is exchanged, preserving the GUIDs keeps links and translations intact.
GUID vs. URI
A GUID is an opaque number with no meaning or resolution mechanism. A Uniform Resource Identifier (URI) follows a scheme and can be resolvable, for example as a web address. A GUID can be turned into a URI with the urn:uuid: scheme.