OpenURL is a type of Uniform Resource Locator (URL) that contains resource metadata for use primarily by libraries. The National Information Standards Organization (NISO) has developed OpenURL and its data container (the ContextObject) as American National Standards Institute (ANSI) standard Z39.88. On 22 June 2006, OCLC was named the maintenance agency for the standard.
The OpenURL standard is designed to support mediated linking from information resources, such as abstracting and indexing databases, (sources) to library services (targets), such as academic journals whether online or in printed or other formats. A "link resolver", or "link-server", parses the elements of an OpenURL and provides links to appropriate targets available through a library. A source is generally a bibliographic citation or bibliographic record used to generate an OpenURL. A target is a resource or service that helps satisfy user's information needs. Examples of targets include full-text repositories, online journals, online library catalogs and other Web resources and services. A source is typically a database that indexes various types of information resources often found in libraries, such as articles, books, patents, etc. Some examples of such databases include Web of Science, Scifinder, Modern Languages Association Bibliography and Google Scholar.