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Learn About EZID

What Is EZID?

What is EZID?

EZID (easy-eye-dee) makes it easy to create and manage long-term, globally unique identifiers for your data and sources, ensuring their future discoverability. Use EZID to:

  • Create identifiers for anything: texts, data, bones, terms, etc.
  • Manage your research objects more easily with shareable, unbreakable links
  • Store citation information for the objects in a variety of formats
  • Fit identifiers into your automated workflows with our standards-based API

Why use EZID?

Open data, open science, open access initiatives are spreading

  • EZID provides a great way to promote open sharing, because it allows the content creator to establish a permanent link to the object.
  • When the object gets cited by others, even if is moved to a new location, the citation reference will always work, as long as the metadata is updated.
  • EZID itself is built with open source components, and clients are contributing open source add-ons as well.
  • And now, EZID is also linked to Crossref, a huge benefit for non-profit open-access publishers that want CrossRef services for their journals.

Funders demand management and tracking

  • The data management plan will save you time and resources in the long run and ensure that the data will be usable in the future.
  • Moreover, the OSTP Public Access Memo requires an approach to "identifying and providing appropriate attribution to scientific data sets" for covered agency public access plans.
  • EZID services can help. Contact your university library or one of our current clients and ask for EZID.

The changing role of the library, with scholarly communication evolving to include data

  • As your Library develops data management and data curation services, you are looking for ways to reach out to scholars and meet their data-related needs.
  • EZID is flexible, affordable and extensible, allowing the Library to sponsor access for all scholars on a campus.
  • The Library can become known as the go-to place for data citation, data sharing, and data management.

Storage has gone global

  • You can offer the EZID services to your clients so that they can register an ARK or DOI now and circulate and cite the clickable addresses to their colleagues.
  • You will appreciate the automated workflows available with EZID's easy application programming interface (API), its standards-based processes, and the growing community of support.

Who is EZID For?

Academic Libraries & Research Libraries

  • Turn your library into a data management service center with EZID
  • Data is part of your institution’s scholarly assets--manage and preserve it!

Scholars, Researchers & Data Centers

  • Increase citations, track your research, improve lab organization, meet funder requirements
  • Choose the identifier scheme that fits your work

Government Agencies

  • Track research impact, improve lab organization

Private Sector Service Providers (laboratory services, publishers, etc.)

  • Show your commitment to the long-term by providing persistent identifiers for your customers' data/documents.

Current Users

EZID Partners and Clients

What our users are saying:

"Assigning DOIs to figshare content through the EZID system allows researchers to efficiently share and cite their research. The great team at the California Digital Library makes assigning DOIs a simple yet well structured process."
"We're very pleased to see EZID working on behalf of its clients to create new partnerships that expand the reach and impact of research and scholarship. Sponsored memberships to Crossref through the California Digital Library open up new possibilities for smaller organizations and those who work with scholars to innovate at the fringes of new publication models, integrating the future of online publication as it assumes various forms."
"EZID gives Open Context critical services that help make our data publications lasting contributions to the scholarly record. Because of EZID, we can explore innovative new approaches in publishing that can be used and cited in years to come."
"The partnership between EZID and Crossref presents an exciting opportunity for eScholarship and our journal partners. The inclusion of our Open Access publications in new discovery services via Crossref, particularly its metadata feed, will dramatically increase the exposure of the important scholarship published on our platform."

Client lists

Complete list of CDL clients

Complete list of Purdue clients


Education and Non-Profit

  • Annual subscription fee
  • Includes creation and maintenance of up to 1 million identifiers per year
Pricing Schedule DOIs and ARKs ARKs only
Assoc/Bac Granting Institution* $500 $300
Masters Granting Institution* $1,000 $600
Research Institution or Non-Profit Organization* $2,500 $1,500
Research group, department, or team $835 $500

For Profit

  • Annual subscription fee
  • Includes creation and maintenance of up to 1 million identifiers per year
Pricing Schedule DOIs and ARKs ARKs only
Small (less than 100 employees) $2,500 $1,500
Medium (100 to 500 employees) contact us contact us
Large (over 500 employees) contact us contact us

* Consortium (3 or more institutions or organizations) 20% discount on any fee marked

For any questions regarding the above categories or rates, please contact us.

University of California researchers: please contact us for UC rates.


Non-technical Documentation

What is a long-term identifier?

An identifier is an association between a character string and an object. Objects can be files, parts of files, names of persons or organizations, abstractions, etc. Objects can be online or offline. Character strings include URLs, serial numbers, names, addresses, etc. A "persistent identifier" is an identifier that is available and managed over time; it will not change if the item is moved or renamed. This means that an item can be reliably referenced for future access by humans and software. EZID currently supports persistence for two kinds of identifiers: DataCite Digital Object Identifiers (DOIs) and lower-cost Archival Resource Keys (ARKs).

What is a DOI?

DOI stands for "Digital Object Identifier." It is an identifier originating from the publishing world and in widespread use for journal articles. DOIs become persistent when the objects and identifier forwarding information are maintained.

What is an ARK?

ARK stands for "Archival Resource Key." It is an identifier originating from the library, archive and museum community. ARKs become persistent when the objects and identifier forwarding information are maintained.

Can DOIs and ARKs be used together?

ARK identifiers have certain features that can be very useful for:

  • Keeping track of many granules of a dataset (ARKs will be able to "pass through" a suffix, so many thousands of items can be referenced on the basis of a single registration);
  • Keeping track of data before a decision has been made about whether or not it is going to be retained (ARKs can be deleted).

This can make it attractive to use ARKs during the early part of a dataset's "life" or the early stages of the research process. Then, when the time comes to begin writing up results and it becomes clear which object(s) will be cited, it may appropriate to get DOIs for those objects.

DOIs have the citation-level "reputation" and it is possible to use the ARK of the cited object as the "suffix" for the DOI so that there is a traceable connection between the two. Here is what that means:

Step 1. You assign an ARK to a resource for good management and tracking: ark:/99999/fk4sf2w65j

Step 2. You decide to cite the resource, so you want a DOI.

Step 3. Using either the Advanced Create UI or the API, request a doi with this form: doi:10.5072/FK2fk4sf2w65j

In this way, the two identifiers have a relationship, so the object can be tracked throughout its life cycle. With EZID, clients get access to both of these identifiers and can take best advantage of both approaches.

What is identifier resolution?

Instead of leading directly to an object, one identifier frequently points to another, or "target URL", that leads directly to the object. The process of getting to the final target name, possibly via a chain of intermediate names, is called "resolution." Resolution on the web is usually fast and invisible. It is done behind the scenes on your behalf by web browsers. Unsuccessful resolution, however, usually means visible failure to access the object that you were expecting, resulting in a "broken identifier." Objects tend to move, so identifier persistence depends on resolution using up-to-date target URLs. To make this happen, EZID provides a way for people to update target URLs as they change when objects move around. This is very similar to leaving a forwarding address when you change your residence. As the starting point for resolution, the resolver effectively lets you publicize an unchanging identifier that you maintain so that it will consistently hit a target that may be moving. EZID currently updates two resolvers: N2T (Name-to-Thing) based at and the DOI (Digital Object Identifier) resolver based at

What is metadata?

Metadata is information (data) about the object, such as the name of the object's creator, the date of creation, the target URL, the version of the object, its title, and so on. EZID allows the user to enter metadata at the same time as an identifier is requested. Associating metadata with identifiers enables more sophisticated mechanisms for digital content discovery and higher-level assurances of long-term persistence.

Who should I contact for more information?

Please contact us with any questions or comments. Also, see Identifier Basics for more information about the identifier practices implemented by the EZID team.

EZID Service Guidelines

Technical Documentation

API Documentation

OAI-PMH Service Documentation

Identifier Basics

Open Source Software for EZID

Suffix Passthrough Explained

Status Information

For information about the status of the EZID system, please consider the following options:

API inquiries

The CDL System Status Page

The EZID Status Blog

The RSS Feed from the Status Blog


What is the relationship between EZID, CDL, and DataCite? And do we have to join DataCite to get DOIs?

By working with CDL and EZID, you are automatically working with DataCite, because CDL is a full DataCite member. This diagram may help explain the relationships.

After the subscription is paid, then what? How do users we want to sponsor get access?

Once the main account is set up, if you would like to sponsor other groups, then you would use the sponsored account order form to request new accounts. Please contact us for this form if you don't have it. In addition, we provide customizable outreach materials and presentations you can re-purpose to use at your institution.

Who sets up accounts for groups? Who sets up accounts for individuals?

CDL handles this. We are developing the functionality so that you can do (some of) this for yourselves. At the present time, this is something we do for you.

We are working with a repository that is using EZID. How are the IDs issued by the repository related to EZID?

If you submit content to a repository working with EZID, the ARKs or DOIs it assigns come from EZID.

Can EZID identifiers be related to the links in other systems?

EZID identifiers can be related to external links if you associate them with metadata, for example by using the relatedIdentifier field in the DataCite metadata schema.

What is the best way to link to the DOIs and ARKs I create with EZID?

If you would like to include clickable links to DOIs and ARKs on a landing page, we recommend that you format them following this html template:

DOI: <a href="">doi:10.1234/ABCD</a>
ARK: <a href="">ark:/12345/abcde</a>
We discourage the practice of publishing or citing links to identifier management pages at because it is generally preferable for search engine crawlers to index resource (object) pages rather than pages of identifier administration details. In this way, users looking for data will be sure to find the landing pages you have prepared.

We have a DSpace repository. Is it possible (or advisable) to apply EZID identifiers retrospectively or in the future for the content in our Dspace repository?

Because EZID has an API, it is possible to write code to interact with your Dspace repository.

What happens when an account holder leaves our institution? Can he or she still update the DOI or ARK? If not, what must happen?

If an account-holder leaves your institution, please let us know so that we revoke their CREATE access to EZID. They will continue to be able to maintain all existing identifiers.

What if research partners are not at our institution? Can they also use EZID for a project partially based at our institution?

If there is a researcher from your institution associated with the project, and if you want to sponsor the access, then we are okay with extending access. Please use the sponsored account order form (see above) to request the new account.

Are we eligible to participate in your Crossref service?

All non-profit institution account-holders are eligible to participate. Please contact us for more information.

Crossref Service FAQs


Webinars and Presentations

2015 & 2016

Introducing the EZID Redesign Webinar from EZID, June 22, 2016

Identifiers made easy with EZID Poster at Dublin Core Metadata Initiative Conference, São Paulo, Brazil, Sept. 1-4, 2015, and at Force2016 Conference, Portland, OR, US, April 18-19, 2016, ppt


Conversations about Data Citation Webinar sponsored by EZID, Sept. 25, 2014

Webinar Introduction Slides, Sept. 25, 2014

Webinar Resource Link Slides, Sept. 25, 2014

Identifiers and Data Management,Talking Points, March 14, 2014, slides


Customizable materials

EZID Flyer

EZID Postcard for STEM outreach

EZID Postcard for Digital Humanities outreach

API Guide