An OpenURL is similar to a web address, but instead of referring to a physical website, it refers to an article, book, patent, or other resource within a website.
OpenURLs are similar to
A permalink or permanent link is a URL that is intended to remain unchanged for many years into the future, yielding a hyperlink that is less susceptible to link rot. Permalinks are often rendered simply, that is, as clean URLs, to be easier to t ...
because they are permanently connected to a resource, regardless of which website the resource is connected to.
Libraries and other resource centers are the most common place to find OpenURLs because an OpenURL can help Internet users find a copy of a resource that they may otherwise have limited access to.
The source that generates an OpenURL is often a bibliographic citation or bibliographic record in a database. Examples of these databases include
Ovid Technologies, Inc. (or just Ovid for short), part of the Wolters Kluwer group of companies, provides access to online bibliographic databases, academic journals, and other products, chiefly in the area of health science
The following ...
, Web of Science
Chemical Abstracts Service
CAS (formerly Chemical Abstracts Service) is a division of the American Chemical Society. It is a source of chemical information. CAS is located in Columbus, Ohio, United States.
''Chemical Abstracts'' is a periodical index t ...
Modern Language Association
The Modern Language Association of America, often referred to as the Modern Language Association (MLA), is widely considered the principal professional association in the United States for scholars of language and literature. The MLA aims to "st ...
and Google Scholar
National Information Standards Organization
The National Information Standards Organization (NISO; ) is a United States non-profit standards organization that develops, maintains and publishes technical standards related to publishing, bibliographic and library applications. It was fou ...
(NISO) has developed standards for OpenURL and its data container as
American National Standards Institute
The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The orga ...
(ANSI) standard ANSI/NISO Z39.88-2004. OpenURL standards create a clear structure for links that go from information resource databases (sources) to library services (targets).
A target is a resource or service that helps satisfy a user's information needs. Examples of targets include full-text repositories, online journals, online library catalogs and other Web resources and services. OpenURL knowledge bases
provide links to the appropriate targets available.
OpenURL was created by
Herbert Van de Sompel
Herbert Van de Sompel is a Belgian librarian, computer scientist, and musician, most known for his role in the development of the Open Archives Initiative (OAI) and standards such as OpenURL, Object Reuse and Exchange, and the OAI Protocol for ...
, a librarian at the University of Ghent
, in the late 1990s. His link-server software, SFX
, was purchased by the library automation company
Ex Libris Group
Ex Libris Group is an Israeli software company that develops integrated library systems and other library software. The company is headquartered in Jerusalem, and has ten other offices around the world. In October 2015, Ex Libris was acquired by ...
which popularized OpenURL in the information industry.
In 2005, a revised version of OpenURL (version 1.0) became ANSI/NISO standard Z39.88-2004, with Van de Sompel's version designated as version 0.1.
The new standard provided a framework for describing new formats, as well as defining
Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. T ...
versions of the various formats.
In 2006 a research report found some problems affecting the efficiency of OpenURL linking and recommended the creation of a group to establish best practice solutions. The KBART
( Knowledge Bases And Related Tools
) working group has been set up to progress the recommendations of the research report.
OpenURL standards and reporting work continues with NISO's IOTA (Improving OpenURLs Through Analytics) project, which produced a reporting tool and research summary in 2013 noting the benefits of data analysis to improve link resolution.
In June 2006, NISO
Online Computer Library Center
OCLC, Inc., doing business as OCLC, See also: is an American nonprofit cooperative organization "that provides shared technology services, original research, and community programs for its membership and the library community at large". It wa ...
(OCLC) as the "maintenance and registration agency" (or "registry agent") of the OpenURL standard, for an initial term of five years.
In 2011, OCLC researchers highlighted their work in a NISO journal article, noting that "the OpenURL standard is one of the most heavily used NISO standards".
As registry agent, OCLC was responsible for reviewing proposed extensions to the standard and maintaining a listing of those it approved.
Per the standard, registry entries could specify particular metadata fields and their representation. The registry had the canonical URL
In 2022, OCLC updated its OpenURL Registry webpage to state that the registry is no longer supported or maintained, saying it had been an "experimental research project" and "research prototype application".
The standard registry URL now redirects to an archived version of the site, described as "the Frozen (deprecated) version of the Registry for the OpenURL Framework".
* NISO OpenURL version 0.1 (2000-05-16)
* NISO OpenURL version 1.0f (2003-03-18)
* ANSI/NISO Z39.88-2004
* ANSI/NISO Z39.88-2004
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The most common application of OpenURL is to assist in the resolution of a request for a web resource (such as an online article). An OpenURL includes information about the referenced resource itself, and context information — both the context in which the OpenURL occurs (for example, a page of search results from a library catalog) and the context of the request (for example, the particular user making the request). If a different context is expressed in the URL, a different copy ends up resolved to. Changes in context are predictable, and do not require the original creator of the hyperlink (for example, the journal publisher) to handcraft different URLs for different contexts.
For example, changing either the base URL or a parameter in the query string can mean that the OpenURL resolves to a copy of a resource in a different library. So the same OpenURL, contained for instance in an electronic journal, can be adjusted by any library to provide access to their own copy of the resource, without completely overwriting the journal's hyperlink. The journal provider, in turn, is no longer required to provide a different version of the journal, with different hyperlinks, for each subscribing library (See also
A coin is a small, flat (usually depending on the country or value), round piece of metal or plastic used primarily as a medium of exchange or legal tender. They are standardized in weight, and produced in large quantities at a mint in order t ...
An OpenURL consists of a base
A Uniform Resource Locator (URL), colloquially termed as a web address, is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it. A URL is a specific type of Uniform Resource Identifi ...
, which contains the address of the user's institutional link-server, followed by a
A query string is a part of a uniform resource locator (URL) that assigns values to specified parameters. A query string commonly includes fields added to a base URL by a Web browser or other client application, for example as part of an HTML, ch ...
, consisting of key-value pairs serializing a ''ContextObject''. The ContextObject is most often bibliographic data, but as of version 1.0 OpenURL can also include information about the requester, the resource containing the
In computing, a hyperlink, or simply a link, is a digital reference to data that the user can follow or be guided by clicking or tapping. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text w ...
, the type of service required, and so forth. For example:
is a version 0.1 OpenURL describing a book.
is the base URL of an example link-server.
In version 1.0, this same link becomes somewhat longer:
The above query string consists of the following key-value pairs:
– specifying the ContextObject version
– specifying the metadata format for the referent (in this case, a book)
* Fields from this format describing the referent object:
The International Standard Book Number (ISBN) is a numeric commercial book identifier that is intended to be unique. Publishers purchase ISBNs from an affiliate of the International ISBN Agency.
An ISBN is assigned to each separate edition and ...
identifying the book
– the title of the book
Keys always consist of safe characters and are not encoded, but values are URL-encoded
Applications and tools
Several companies market link server systems. Some