EZID is a Web service for managing persistent, unique identifiers for research data and potentially other digital resources. It allows users to register identifiers, supply citation metadata, and provide URLs to which the identifiers should resolve. It supports the use of both ARKs (Archival Resource Keys) and DataCite DOIs (Digital Object Identifiers).

It supports various workflows, but the usual pattern is for a library or academic department to subscribe to the service; individual users (researchers) then open accounts that are linked to the group account.


California Digital Library

Licensing and cost

Use of the service requires an annual subscription. The fee charged depends on the type and size of organization, and whether the subscriber wishes to register DOIs as well as as ARKs.

Subscribers can register up to 1 million identifiers per year. Other terms of use are described in the Service Guidelines (PDF).

Development activity

The service is being actively maintained and developed.

Platform and interoperability

EZID can be used through a simple web form so there are no particular platform requirements. Machine access is provided through an API based on REST (Representational State Transfer) principles.

The Merritt repository uses EZID to manage identifers.

Functional notes

If an individual user leaves the institution holding the group account, they can continue to update information about their existing identifiers but lose the ability to create new ones.

Documentation and support

The EZID website provides Service Guidelines (PDF), an FAQ page, documentation explaining the API, and hints for creating good identifiers. Service status reports are provided, and support is available via email.


The web form for interacting with the service is simple and straighforward, with detailed pop-up guidance explaining how the form elements should be completed. There is a simple form for quick use, and an advanced form providing more options and metadata fields.

Expertise required

No expertise is required to use the service, beyond an appreciation of how identifiers should be used and managed; the website itself provides this if the user is unsure.

Standards compliance

The service complies with the metadata requirements of both ARKs and DataCite.

Influence and takeup

The website provides a list of organizations using EZID. There is substantial variety of type among the organizations mentioned, and the list shows the service is used in Europe as well as the United States.

Last reviewed: 
28 April, 2014