Identifier services

Stamp on an ink pad with "ISNI" written on it.

The British Library is a registration agency for the following identifiers: DOI via DataCite, ISSN, ISNI, ISIL, and MARC organization codes.

Our identifier services enable the unique identification of:

  • datasets for commerce, research, interoperability and discovery
  • new or changed titles of serials published in the UK
  • persons and corporate bodies
  • UK libraries and related organisations.

DOI: Digital Object Identifier

The DOI is the Digital Object Identifier system (ISO 26324), managed by the International DOI Foundation. DOIs are persistent identifiers that are used to uniquely identify an object (which may itself be physical or digital) in the digital environment.
The British Library is a founding member of DataCite. We work with UK organizations to ensure their data, software and other research items can be uniquely identified with DOIs.

ISSN: International Standard Serial Number

The ISSN is the international Standard Serials Number (ISO 3297) that uniquely identifies serial publications.

The British Library hosts ISSN UK. We are the national centre responsible for assigning ISSN to serials published in the United Kingdom. The ISSN International Centre provides information on other ISSN National Centres.

ISNI: International Standard Name Identifier

The ISNI is the International Standard Name Identifier (ISO 27729) for identifying the millions of contributors to creative works and those active in their distribution, including researchers, inventors, writers, artists, visual creators, performers, producers, publishers, aggregators and more.

The British Library is a Registration Agency for the ISNI. We are working with partners in the cultural, research and publishing communities to assign ISNIs to persons and organisations. We're also integrating ISNIs in our cataloguing and authority workflows.

The Library is assigning ISNIs to all new authors in our e-theses online service, EThOS.

In April 2021, the Library launched the ISNI Portal. It enables users to register new ISNIs as well as add data to their own ISNI records.

For further information, please contact

ISIL: International Standard Identifier for Libraries and related organisations

The ISIL is the International Standard Identifier for Libraries and related organization (ISO 15511). An ISIL can be assigned to a library or related organisation. An ISIL can also be assigned to sub-units of an organisation. ISIL is a requirement of the UK Data Model for implementation of ISO 28560/2 RFID in libraries -- Part 2: Encoding of RFID data elements based on rules from ISO/IEC 15962.

The British Library is the UK National Agency for the assignment of the ISIL to organisations in the UK, Crown Dependencies and Overseas Territories.

MARC organization code

MARC organization codes (formerly known as NUC codes) represent names of libraries, other kinds of organisations or sub-units of organisations that need to be identified in the bibliographic environment.

The British Library assigns MARC codes for organizations in the UK, Crown Dependencies and Overseas Territories.


Get a MARC organisation code

Make sure your library or related institution is identifiable in the bibliographic environment.

Get an ISIL for your library

We assign International Standard Identifiers to libraries and related organisations in the UK.

Get an ISBN or ISSN for your publication

These identifiers are used for distributing, describing and selling publications