api_format.md

Crossref Metadata API JSON Format

Versioning

Version	Release Date	Comments
v1	11th July 2016	First documented version
v2	26th July 2017	Add abstract, authenticated-orcid, fix contributor fields

Work

Field	Type	Required	Description
publisher	String	Yes	Name of work's publisher
title	Array of String	Yes	Work titles, including translated titles
original-title	Array of String	No	Work titles in the work's original publication language
short-title	Array of String	No	Short or abbreviated work titles
abstract	XML String	No	Abstract as a JSON string or a JATS XML snippet encoded into a JSON string
reference-count	Number	Yes	Deprecated Same as references-count
references-count	Number	Yes	Count of outbound references deposited with Crossref
is-referenced-by-count	Number	Yes	Count of inbound references deposited with Crossref
source	String	Yes	Currently always Crossref
prefix	String	Yes	DOI prefix identifier of the form http://id.crossref.org/prefix/DOI_PREFIX
DOI	String	Yes	DOI of the work
URL	URL	Yes	URL form of the work's DOI
member	String	Yes	Member identifier of the form http://id.crossref.org/member/MEMBER_ID
type	String	Yes	Enumeration, one of the type ids from https://api.crossref.org/v1/types
created	Date	Yes	Date on which the DOI was first registered
deposited	Date	Yes	Date on which the work metadata was most recently updated
indexed	Date	Yes	Date on which the work metadata was most recently indexed. Re-indexing does not imply a metadata change, see deposited for the most recent metadata change date
issued	Partial Date	Yes	Eariest of published-print and published-online
posted	Partial Date	No	Date on which posted content was made available online
accepted	Partial Date	No	Date on which a work was accepted, after being submitted, during a submission process
subtitle	Array of String	No	Work subtitles, including original language and translated
container-title	Array of String	No	Full titles of the containing work (usually a book or journal)
short-container-title	Array of String	No	Abbreviated titles of the containing work
group-title	String	No	Group title for posted content
issue	String	No	Issue number of an article's journal
volume	String	No	Volume number of an article's journal
page	String	No	Pages numbers of an article within its journal
article-number	String	No
published-print	Partial Date	No	Date on which the work was published in print
published-online	Partial Date	No	Date on which the work was published online
subject	Array of String	No	Subject category names, a controlled vocabulary from Sci-Val. Available for most journal articles
ISSN	Array of String	No
issn-type	Array of ISSN with Type	No	List of ISSNs with ISSN type information
ISBN	Array of String	No
archive	Array of String	No
license	Array of License	No
funder	Array of Funder	No
assertion	Array of Assertion	No
author	Array of Contributor	No
editor	Array of Contributor	No
chair	Array of Contributor	No
translator	Array of Contributor	No
update-to	Array of Update	No
update-policy	URL	No	Link to an update policy covering Crossmark updates for this work
link	Array of Resource Link	No	URLs to full-text locations
clinical-trial-number	Array of Clinical Trial Number	No
alternative-id	String	No	Other identifiers for the work provided by the depositing member
reference	Array of Reference	No	List of references made by the work
content-domain	Content Domain	No	Information on domains that support Crossmark for this work
relation	Relations	No	Relations to other works

Work Nested Types

Funder

Field	Type	Required	Description
name	String	Yes	Funding body primary name
DOI	String	No	Optional Open Funder Registry DOI uniquely identifing the funding body
award	Array of String	No	Award number(s) for awards given by the funding body
doi-asserted-by	String	No	Either crossref or publisher

Clinical Trial Number

Field	Type	Required	Description
clinical-trial-number	String	Yes	Identifier of the clinical trial
registry	String	Yes	DOI of the clinical trial regsitry that assigned the trial number
type	String	No	One of preResults, results or postResults

Contributor

Field	Type	Required	Description
family	String	Yes
given	String	No
ORCID	URL	No	URL-form of an ORCID identifier
authenticated-orcid	Boolean	No	If true, record owner asserts that the ORCID user completed ORCID OAuth authentication
affiliation	Array of Affiliation	No

Affiliation

Field	Type	Required	Description
name	String	Yes

Date

Field	Type	Required	Description
date-parts	Array of Number	Yes	Contains an ordered array of year, month, day of month. Note that the field contains a nested array, e.g. [ [ 2006, 5, 19 ] ] to conform to citeproc JSON dates
timestamp	Number	Yes	Seconds since UNIX epoch
date-time	String	Yes	ISO 8601 date time

Partial Date

Field	Type	Required	Description
date-parts	Array of Number	Yes	Contains an ordered array of year, month, day of month. Only year is required. Note that the field contains a nested array, e.g. [ [ 2006, 5, 19 ] ] to conform to citeproc JSON dates

Update

Field	Type	Required	Description
updated	Partial Date	Yes	Date on which the update was published
DOI	String	Yes	DOI of the updated work
type	String	Yes	The type of update, for example retraction or correction
label	String	No	A display-friendly label for the update type

Assertion

Field	Type	Required	Description
name	String	Yes
value	String	Yes
URL	URL	No
explanation	URL	No
label	String	No
order	Number	No
group	Assertion Group	No

Assertion Group

Field	Type	Required	Description
name	String	Yes
label	String	No

License

Field	Type	Required	Description
content-version	String	Yes	Either vor (version of record,) am (accepted manuscript,) tdm (text and data mining) or unspecified
delay-in-days	Number	Yes	Number of days between the publication date of the work and the start date of this license
start	Partial Date	Yes	Date on which this license begins to take effect
URL	URL	Yes	Link to a web page describing this license

Resource Link

Field	Type	Required	Description
intended-application	String	Yes	Either text-mining, similarity-checking or unspecified
content-version	String	Yes	Either vor (version of record,) am (accepted manuscript) or unspecified
URL	URL	Yes	Direct link to a full-text download location
content-type	String	No	Content type (or MIME type) of the full-text object

Reference

Field	Type	Required	Description
key	String	Yes
DOI	String	No
doi-asserted-by	String	No	One of crossref or publisher
issue	String	No
first-page	String	No
volume	String	No
edition	String	No
component	String	No
standard-designator	String	No
standards-body	String	No
author	String	No
year	String	No
unstructured	String	No
journal-title	String	No
article-title	String	No
series-title	String	No
volume-title	String	No
ISSN	String	No
issn-type	String	No	One of pissn or eissn
ISBN	String	No
isbn-type	String	No

ISSN with Type

Field	Type	Required	Description
value	String	Yes
type	String	Yes	One of eissn, pissn or lissn

Content Domain

Field	Type	Required	Description
domain	Array of String	Yes
crossmark-restriction	Boolean	Yes

Relations

A hashmap containing relation name, Relation pairs.

Relation

Field	Type	Required	Description
id-type	String	Yes
id	String	Yes
asserted-by	String	Yes	One of subject or object