Metadata Delivery

The collective power of members’ metadata is available for use in a variety of tools and APIs that allow anybody to search and reuse our metadata in sophisticated ways. Watch the video below to find out more about our Metadata APIs:



Lots of people need to incorporate scholarly metadata into their software and services. For example:

  • Manuscript tracking systems
  • Bibliographic management software
  • Library systems
  • Author profiling tools
  • Specialist subject databases
  • Scholarly sharing networks

The resulting dissemination of metadata enhances content discoverability. The widespread use of our APIs helps to ensure that the entire community can create robust, persistent and accurate citations of our members’ content, to the benefit of publishers, readers and the organizations that use our metadata delivery services.

How it works

There are two main approaches for getting metadata:

  1. User Interfaces for people: the first table lists a few user interfaces that we provide to access metadata, but you may want to start with our newest, open, most comprehensive, and easiest-to-use human interface, Metadata Search.

  2. APIs for machines: the second table lists a few APIs, but we recommend you first look at our newest and most flexible service, our REST API. Take a look at a list of some of the organizations who rely on our REST API.

If you’re interested in using these tools or APIs for production services, we’ll soon have a service-level offering with access to all supported APIs and metadata, but with extra service and support guarantees. If you are interested in the upcoming service-based offering or the other services please contact our outreach team.

Currently we also have two fee-based services - Crossref Metadata Services (CMS) and Affiliate query accounts that use some of the APIs listed below.

Content negotiation

The APIs listed here provide metadata in a variety of representations (aka output formats). If you want to get access to our metadata in a particular representation (e.g. RDF, BibTex, XML, CSL), you can use content negotiation to retrieve the metadata for a DOI in the representation you want. Content negotiation is supported by a number of DOI registration agencies including Crossref, DataCite, and mEDRA.

How to participate - Machine interfaces (APIs) for accessing metadata

We have a number of APIs for accessing metadata. There is one general purpose API and several specialized ones. The specialized APIs are either designed for our members so that they can manage their metadata or they are APIs based on standards that are popular in the community. Watch the video underneath the table below to find out more:

API Name Description
REST API The REST API enables sophisticated, flexible machine and programmatic access to search and filter our metadata. It can be used for example to look up the metadata for a content item or submit a query on an author’s name or find retractions registered with us. It also allows users to search and filter on a number of elements, including a funder, finding all content items with ORCID iDs.
OAI-PMH This API uses a standard popular with the library community that lets you harvest metadata. This is the API used for Crossref Metadata Services (CMS)
Plus service Starting in 2018, users have an option to access both OAI-PMH and the REST API with additional features, such as notifications of new matching records and enhanced service, such as guaranteed uptime.
OpenURL This API lets you lookup a Crossref DOI for a reference using a standard that is popular in the library community and particularly with link resolver services.
XML API This has primarily been used by our members to manage their reference metadata.
XML query API This is primarily used by our members to asynchronously batch process matching references to DOIs.

How to participate - User interfaces for accessing metadata

Crossref provides a number of user interfaces to access Crossref metadata. Some are general purpose, and others are more specialized.

Service Name Description
Metadata Search Metadata Search is our primary user interface for searching and filtering of our metadata. It allows users to quickly enter any term and users can search and filter on a number of elements, including ISSN, ORCIDs, funding data and more.It can be used to lookup the DOI for a reference or a partial reference or a set of references.
Simple text query Simple text query is a tool designed to allow members to easily link their references via DOIs. It allows a member to look up DOIs for multiple formatted references at a time and then deposit these in order to fulfill their reference linking obligations.


Obligations & fees

We assert no claims of ownership to individual items of metadata and associated Digital Object Identifiers (DOIs).

Some of the APIs above are openly available at no cost, some require free registration and some are available for a fee under a specific agreement.

Our fees page lists costs for paid services.

Best practice

It is important that members understand how metadata is used by third parties. We encourage you to get in touch with our outreach team to share your use case with us!


We offer help documentation for all metadata delivery services.

Please contact our member services team with any questions or to get set up, or contact our support team for any technical or troubleshooting questions.

Last Updated: 2017 October 24 by Jennifer Kemp