Web service: xISBN

The xISBN Web service supplies ISBNs and other information associated with an individual intellectual work that is represented in WorldCat. Submit an ISBN to this service, and it returns a list of related ISBNs and selected metadata.

Ideal for Web-enabled search applications—such as library catalogs and online booksellers—and based on associations made in the WorldCat database, xISBN enables an end user to link to information about other versions of a source work.

How xISBN works

ISBNs are related to each other in WorldCat using 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 xISBN Web service queries database tables in WorldCat created by the FRBR algorithm.

Using the xISBN Web service

To use the service, you submit a single, known ISBN value embedded in a URL to the xISBN server, and the server returns a list of associated ISBNs and relevant metadata. The ISBNs are sorted by the number of times each represented item is held by a WorldCat library, highest to lowest. Therefore, the first returned ISBN represents the most-held item in WorldCat among all associated items.

You may receive associated ISBNs in either XML or XHTML format. The xISBN server supports REST-based requests as well as the OpenURL and unAPI protocols.

The ISBNs returned from the service can in turn be re-used in an "or" query to a bibliographic database to improve the chances of an end user finding all instances of the work in a given database. For example, a user finding an item of interest at an online bookseller could conveniently query a local library's online catalog to find out if any editions or printings of the item are held by the library.

Important notices

• Use of this Web service is governed by WorldCat Affiliate Terms and Conditions
• The xISBN API is available for non-commercial use by developers. Commercial use is possible by prior arrangement. Contact xisbn-support@oclc.org for more information about commercial use.
• The xISBN service is stable and fast under heavy loads, but it is not designed for large numbers of queries submitted by a single user. If your application uses more than 500 requests per day, please contact us and we will work with you to support the application.
• To be kept up-to-date on changes and additions to xISBN and related services, subscribe to the xIdentifier mailing list.
• The old xISBN service is still supported, but developers are urged to begin using the new xISBN service.