GUID

GUID (Globally Unique Identifier) is a Microsoft-originated term for a 128-bit value generated to be unique across systems without central coordination, and it is structurally identical to a Variant-2 UUID as defined by RFC 4122. In research-information and scholarly-communications contexts, ‘GUID’ is also used loosely as a catch-all for any opaque, system-assigned global identifier attached to a record — a repository’s internal record ID, a submission system’s manuscript ID, or a vendor-issued identifier that is not itself a registered persistent identifier scheme. That informal usage is the main source of confusion the term causes on this site: a GUID and a persistent identifier (PID) such as a DOI, ORCID iD, or ROR ID solve related but distinct problems, and conflating them leads to broken assumptions about resolvability and governance.

GUID vs. UUID vs. persistent identifier: what actually differs

The three terms are often used interchangeably but are not equivalent:

• UUID has a single normative specification (RFC 4122, and its 2024 successor RFC 9562, which added new time-ordered UUID versions 6-8). A UUID is a randomly or algorithmically generated 128-bit value with no external registry, no resolution service, and no owning organisation — its uniqueness comes from the astronomically low probability of collision, not from central issuance.
• GUID has no single normative definition of its own. The literal Microsoft GUID (used throughout Windows APIs, COM/ActiveX object identifiers, and .NET’s System.Guid type) is the Variant-2 UUID format under a different name; Microsoft’s own documentation treats the two as interchangeable. Outside Microsoft platforms, ‘GUID’ is frequently used as informal shorthand for “some opaque unique string,” without implying RFC 4122 structure at all.
• Persistent identifier (PID) is a different category altogether: a PID is issued and maintained by a governing registration agency (Crossref or DataCite for DOIs, ORCID for researcher iDs, the Research Organization Registry for institutions) under a defined governance and resolution infrastructure, so that the identifier continues to resolve to current metadata even if the underlying record moves. A bare GUID or UUID carries no such guarantee — nothing resolves it unless the system that generated it chooses to expose a lookup service.

Why this distinction matters for research administration

Research-information systems (CRIS platforms, grant-management systems, repository software) routinely generate an internal GUID for every record the moment it is created — long before, or even instead of, registering a real persistent identifier for that record. Two practical consequences follow:

• A record’s internal GUID is not portable. It has meaning only inside the system that generated it; migrating to a new CRIS or repository platform typically discards the old GUID entirely, which is exactly the failure mode PID infrastructure (DOI, ROR ID, ORCID iD) is designed to prevent.
• A GUID should never be cited, published, or used as a persistent link in place of a proper PID. If a dataset, publication, or grant record needs a durable, externally resolvable reference, the correct target is a registered DOI (via Crossref or DataCite), a ROR ID for the affiliated organisation, or an ORCID iD for the researcher — not the system’s internal GUID, even though the GUID may appear in the record’s metadata or URL.

Worked example

A researcher uploads a dataset to an institutional repository. The repository’s underlying database assigns the record an internal GUID (e.g. a UUID string used as the primary key and embedded in the record’s admin URL) the instant the upload form is submitted. Separately, once the record is reviewed and published, the repository mints a DataCite DOI and registers it with the institution’s DOI prefix. The GUID continues to exist as an internal database key; the DOI is what should be cited in a paper, a data availability statement, or a grant report. Citing the internal GUID instead would produce a link that stops working the moment the repository migrates platforms.

Counter-example

A vendor-issued “Article GUID” appearing in a publisher’s XML feed (common in JATS and similar publishing-industry XML formats) is not a registered persistent identifier even though it looks similarly opaque to a UUID — it is a publisher-internal tracking value, scoped to that publisher’s own systems, and carries no external resolution guarantee. It should not be treated as equivalent to the article’s DOI, which is the identifier actually meant for citation and long-term resolution.

References

• Leach, P., Mealling, M., Salz, R., RFC 4122: A Universally Unique IDentifier (UUID) URN Namespace, IETF, 2005.
• Davis, K., Peabody, B., Leach, P., RFC 9562: Universally Unique IDentifiers (UUIDs), IETF, 2024 (successor to RFC 4122, adds time-ordered UUID versions 6-8).
• Microsoft, “GUID Structure” (Win32 API documentation) and System.Guid (.NET API documentation).