olid

OLID stands for Open Library Identifier, a persistent identifier used by the Open Library project to uniquely identify items within its catalog. The term is often written as OLID or in plural as OLIDs. OLIDs are assigned to three main object types in Open Library: authors, works, and editions, and they are intended to remain associated with an item even as metadata changes over time.

The typical OLID format begins with the letters OL, followed by a sequence of digits and a suffix letter that denotes the type of object. Common examples include OL1A for an author and OL45883W for a work. Editions also have OLIDs, with suffixes that reflect their type. These IDs are used in Open Library URLs and API responses, making OLIDs a stable reference point for linking, data retrieval, and integration with other bibliographic data.

OLIDs serve several purposes within Open Library. They enable precise linking to author pages, work records, and edition records, and they appear in the site’s user interface, data exports, and programmatic APIs. By providing a single, stable identifier across various data representations, OLIDs help reconcile information from different sources, map ISBNs and other identifiers, and support data interoperability with external catalogs and services.

Limitations and scope should be noted. OLIDs are specific to Open Library and its data model; they are not universal identifiers across all libraries. An item may have multiple editions with distinct OLIDs, and some older or less-documented items may lack an OLID altogether.

See also: Open Library, bibliographic identifiers, ISBN and other cataloging identifiers.