xISBN (Web service)
Use this Web service to map book-related identifiers (ISBN, LCCN, OCLC number), based on WorldCat information. Free and subscription versions are available.
The xOCLCNUM Web service is released as part of xISBN service. Submit an OCLC or LCCN number to this service, and it returns a list of related OCLC numbers and selected metadata. The service is based on WorldCat, the world's largest network of library content and services. Current xOCLCNUM database statistic information is available from here. xOCLCNUM API document covers more details about the API.
OCLC numbers are related to each other using librarian-catalogued bibliographic records in WorldCat with an algorithm developed by OCLC Research. The algorithm restructures WorldCat bibliographic records to conform to the FRBR conceptual model for information objects. For instance, rather than requiring an end user to traverse multiple records that represent many different manifestations of a book—including printings, hardback or paperback editions or even filmed versions—"FRBRized" WorldCat information allows that user to review a core record that lists all manifestations.
The xOCLCNUM Web service queries database tables in WorldCat created by the FRBR algorithm.
To use the service, you submit a single, known OCLC or LCCN number value embedded in a URL to the xOCLCNUM server, and the server returns a list of associated OCLC numbers and relevant metadata. The OCLC numbers are sorted by the number of times each represented item is held by a WorldCat library, highest to lowest. Therefore, the first returned OCLC number represents the most-held item in WorldCat among all associated items.
You may receive associated OCLC numbers in either XML, XHTML, Python, JSON, PHP, or Ruby format.
xOCLCNUM is released as part of xISBN project, therefore all access control model are also applicable to xOCLCNUM project. All xOCLCNUM requests are counted as xISBN requests.
Technically, we are trying to keep xOCLCNUM service as close as possible to xISBN service for easy development, however, they are not exactly same API because identifiers can support different types of services, e.g. it's useful to support a fixChecksum method for ISBN, whereas there is no similar concept in OCLC number. To learn more details about xOCLCNUM service, please read API document.