Key Facts on Digital Object Identifier System

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Key concepts and abbreviations

  • DOI = Digital Object Identifier
  • IDF = International DOI Foundation (operating and governing organisation):
  • RAs = DOI Registration Agencies (= members of IDF offering the system to customers who wish to assign DOI names)

Status: operational system

  • Foundation launched to develop system in 1998. First applications launched 2000
  • Currently used by well over 5,000 assigners, e.g., publishers, science data centres, movie studios, etc.
  • Approximately 275 million DOI names assigned to date
  • Over 155,000 DOI name prefixes within the DOI System
  • Approximately 1 billion DOI resolutions per month
  • DOI names are assigned by multiple RAs worldwide
  • Over 30 million shortDOI links to DOI names are in use
  • Initial applications are simple redirection — a persistent identifier
  • More sophisticated functionality available, e.g., multiple resolution, data typing
  • International Standard: ISO 26324, Digital Object Identifier System, 1 May 2012 (available from the ISO Store)


  • Digital Identifier of an Object (not “Identifier of a Digital Object”)
  • Object = any entity (thing: physical, digital, or abstract)
    • Resources, parties, licences, etc.
  • Digital Identifier = network actionable identifier (“click on it and do something”)
  • Generic framework
  • Initial focus on entities was documents/media e.g., articles, data sets
    • Now also moving into parties and licences
    • Extending to other sectors
  • Extensible by design to any sector: not intended as a publishing-only solution (digital convergence)
  • International coverage

What it does

  • Provides an actionable, interoperable, persistent link
  • Actionable – through use of identifier syntax and network resolution mechanism (Handle System®)
  • Persistent – through combination of supporting improved handle infrastructure (registry database, proxy support, etc) and social infrastructure (obligations by Registration Agencies)
  • Interoperable – through use of a data model providing semantic interoperability and grouping mechanisms


  • IDF = operating and governing organisation
  • Provides the social infrastructure
    • e.g., obligations for persistence, back-up, in event of failure, etc.
  • Proven model: successfully transitioned the management of persistent identifiers between different registrants and between different RAs
  • US “Not for profit” open membership (with membership fee)
  • Federation of Registration Agencies makes up majority of the IDF
  • Elected Board
  • No full time staff (contracted outsourced functions)

Business Model

  • IDF receives membership fees from RAs, contracts technical operator
  • RAs are members of IDF and pay a fixed fee per year
  • Costs of operating the system are divided across RAs so that IDF is cost-neutral
  • Assigners are customers of RAs
  • RAs might have their own existing numbering scheme, existing communities etc. – which can be integrated with a DOI Application not replaced by it.
  • RAs are autonomous independent bodies. They offer services to assigners using DOI names
    • RAs’ business model with their customers is entirely autonomous
    • RAs only obligation to IDF is a licence/operating agreement
    • RAs may choose to put DOI names “under the hood”
  • Some RAs are commercial; others are themselves member communities

Technical Infrastructure

  • Handle System: persistent identification in digital networks
  • Vocabulary Mapping Framework: data dictionary methodology for associated metadata
  • Both used elsewhere: aim was not to re-invent the wheel


  • ISO 26324, Information and Documentation — Digital Object Identifier System (2012)
  • Mechanism for, and emphasis on, enabling re-use of other existing identifier schemes, e.g., ISBN; see “DOI System and Standard Identifier Schemes”.



  • 1996 proposal from the three major international publishing trade associations to develop infrastructure for digital publishing;
  • Need in the digital supply chain for an equivalent of the analogue bar code: migration from analogue to digital networked content cannot rely on URLs as identifiers (e.g., due to “linkrot”: “404 not found”)

Relation to other schemes

  • Strong focus on interoperability and on working with existing and new schemes; technical, syntactic, and semantic interoperability
  • Adopt existing proven components

Intellectual Property Considerations

  • IDF owns DOI®, a registered trademark for the system
  • IDF does not have any patents (or patent applications) on DOI System
  • IDF collectively licences appropriate technology from suppliers on behalf of members
  • Patent Policy in place
  • All RAs must sign RA agreement re use of IDF System
  • IDF is a participant in related projects
Updated December 1, 2021