CrossRef is a not-for-profit network founded on collaboration between publishers. CrossRef aims to make reference linking throughout online scholarly literature efficient and reliable. It provides an infrastructure for linking citations across publishers and a collaborative reference linking service that functions as a sort of digital switchboard. It holds no full-text content, but rather provides links through digital object identifiers (DOIs). Every electronic journal article has a unique alphanumeric string (its DOI) that is associated with tagged metadata supplied by the participating publishers and a URL pointer, thereby providing a persistent link to its location on the Internet. CrossRef does not aggregate full-text content; instead it uses a system of 'distributed aggregation' whereby full-text content is linked through a database consisting of minimal publisher metadata. Each record in the database is essentially a triplet: metadata plus URL plus DOI. In this way CrossRef has developed a scalable linking system through which a researcher can click on a reference citation in a journal and access the cited article.

CrossRef was developed by a group of international scholarly publishers. The initial service was based on a prototype developed by John Wiley & Sons and Academic Press, in cooperation with the International DOI Foundation (IDF). It built on the DOI-X project led by the IDF, Association of American Publishers (AAP) and the Corporation for National Research Initiatives (CNRI).

At the beginning of 2000, several publishers joined to form the Publishers International Linking Association, Inc. (PILA), the non-profit, independent organization that operates CrossRef. The Board of Directors comprises representatives from AAAS (publisher of Science), American Institute of Physics, Association for Computing Machinery, American Psychological Association, Blackwell Publishers, Elsevier Science, American Institute of Electrical Engineers, Kluwer Academic Publishers, Nature, Oxford University Press, Sage Publications, Springer Verlag, and Wiley. CrossRef went live as the first collaborative reference linking service in June 2000. Any publisher of primary research material in digital form can become a member and register its content with CrossRef.

CrossRef aims to promote the development and cooperative use of new and innovative technologies to speed and facilitate scholarly research. CrossRef serves as a citation-linking backbone for all scholarly literature online, in order to lower the barriers to content discovery and access for researchers.

Static URLs are not a persistent linking mechanism. If a URL is published as a link and the content it points to is moved, then that link will no longer function. CrossRef relies on DOIs to address this problem. Publishers can move content from one production system to another (pre-print to post-print), or from one publisher to another. In these cases the publisher simply updates the DOI directory; the DOI itself never changes, which means that all the links to that content that have already been propagated still function. Because a DOI link is a persistent link, unlike a URL, CrossRef creates reliable and persistent links in citations and database records.