Home > Metadata for e-books


The library networks and institutions (BVB, DNB, GBV, hbz, hebis, KOBV, OBV, SLSP, SWB, ZDB) that are members of the Arbeitsgemeinschaft der Verbundsysteme (AGV) /  Consortium of Library Networks and the Arbeitsgruppe Kooperative Verbundanwendungen (AG KVA) / Cooperative network applications working group describe their requirements for metadata for licensed e-books for all data providers [ 1] . The library networks process metadata on e-books and e-book packages regularly and in large numbers for their member libraries - from importing into the database to presentation on the user interfaces. The completeness and quality of the data is particularly important for the research experience of users in the libraries, whose needs are to be optimally supported.

All library networks and institutions are set up to receive and process metadata in the MARC 21 and/or ONIX for Books 3.0.8 formats. As a publisher or data producer, you have the freedom to decide which delivery format you choose or prefer within the scope of your technical framework and possibilities. For both formats, we describe data elements in the online documentation that are of crucial importance for processing and for the information content of the metadata and provide information on what needs to be taken into account when assigning them. In this respect, this documentation is not a replacement for the official format documentation for MARC 21[2] and ONIX for Books 3.0.8[3], but only describes an excerpt from them. Important structural information on the structure of a MARC 21 data record or the creation of a message in ONIX 3.0.8 can also only be found in the original documentation; we do not go into this in our requirement descriptions. For the use of ONIX for Books 3.0.8, we also refer to the VLB-ONIX-Empfehlungen[4] of MVB GmbH, which also provided us with some important points of reference[5].


The documentation of the requirements is structured according to data elements. For the data elements and their naming, we use the common terms of the book trade and publishing industry wherever possible. For each data element, an overview page shows in tabular form whether it is mandatory or optional in the metadata and which field in MARC 21 or which tag in ONIX 3.0.8 should be used for it. If certain specifications are to be observed when filling the elements in the data records, this is indicated separately. Examples are also given for both format variants to illustrate the specifications.

Notes on MARC 21

In addition to the elements/fields explicitly described in the requirements, other fields, some of which are mandatory, are required to create a structurally valid MARC 21 data record. Please refer to the official and detailed MARC 21 documentation for more information on this and on the two indicators to be set at the beginning of the MARC 21 fields. In the examples the indicators have been taken into account. The "blank" indicator is represented by the # character.

Notes on ONIX for Books 3.0.8 (reference version)

What has already been said for MARC 21 also applies here: In order to generate a structurally valid ONIX message, further mandatory elements must be provided in addition to those specified in the requirements. To make it clear which element is meant in ONIX and what its position is in the message structure, we show the entire hierarchy for each element within which the element is found in the message. The individual elements are listed both as "Reference names" and as "Short tags" in the tabular overview. Here too, the choice between the two variants lies with the publisher or data producer and always applies to a complete message. The use of an element may structurally require the specification of further binding elements within an element group without this being explicitly described in the requirements. The examples in the text also focus mainly on the elements that are expected in metadata deliveries and do not always include all mandatory elements of the relevant composite.


The requirements described remain stable until changes in the delivery formats or other current developments make adjustments necessary. Such adjustments are incorporated directly into the documentation so that it is always up to date. Fundamental changes to content are documented in an update history.

Need for discussion or clarification/suggestions

If you have any questions about the requirements described, discover unclear text passages that require clarification or have suggestions for an improved presentation, we look forward to hearing from you at any time by contacting one of the partners involved [6]:

Bibliotheksservice-Zentrum Baden-Württemberg (BSZ)

Bibliotheksverbund Bayern

Deutsche Nationalbibliothek

Verbundzentrale des Gemeinsamen Bibliotheksverbundes (GBV|VZG)

Hochschulbibliothekszentrum des Landes Nordrhein-Westfalen (hbz)


Hotline des KOBV -  Kooperativer Bibliotheksverbund Berlin-Brandenburg

Die Österreichische Bibliothekenverbund und Service GmbH

[ 1] When submitting national and regional deposit copies, metadata requirements may differ in detail. These are defined by the responsible deposit libraries.

[2] MARC 21 Format for Bibliographic Data. https://www.loc.gov/marc/bibliographic/

[3] ONIX for Books 3.0.8 Specification + Codelists Issue 60. https://www.editeur.org/files/ONIX%203/ONIX_for_Books_Release3-0_docs+codes_Issue_60.zip

[4] VLB-ONIX-Empfehlungen. https://vlb.de/hilfe/vlb-onix-empfehlungen (in German)

[5] We would like to thank MVB GmbH for their kind permission to use short text passages - especially definitions - from the VLB-ONIX-Empfehlungen.

[6] To avoid spam messages, the usual at sign has been replaced by the character string [at] in all e-mail addresses.