Frequently Asked Questions about the DOI^® System

These "Frequently Asked Questions" about the DOI system and DOI^® names are not meant to take the place of the fuller information available in the DOI Handbook; where possible, we provide pointers to the relevant section of the handbook. If you have a question that you think should be added to this list, or is not satisfactorily answered, please feel free to contact us at contact@doi.org.

See also the DOI Handbook, Glossary of Terms, for definitions of related terms, and the Handle System^® FAQs to learn about the underlying handle resolution technology.

1. How do I use the DOI system for my material?

You can join a service offered by a DOI Registration Agency (see list) by registering your material with them. If you do not see an appropriate application listed, consider approaching an existing agency or developing a community to build one.

See the DOI Handbook, 8 Registration Agencies, for more information.

2. How much does it cost to use the DOI system?

Existing DOI names can be resolved free of charge. The cost of registering new DOI names depends on the services using a DOI which you are purchasing from a Registration Agency. Contact an appropriate Registration Agency to discuss your options. Each Registration Agency is free to offer its own business model; the IDF does not determine the costs charged to end users.

For an example of the costs of a DOI service, see the CrossRef publisher fees.

3. Can I search to see what already has a DOI name?

Many web search engines will show DOI names in search results, from a topic search, or from a search on specific terms that apply to the items you are looking for. The DOI system does not provide a central facility to search across all DOI names by looking at the metadata. However, this sort of query facility (searching from metadata to find a DOI name) may be offered by Registration Agencies or other services for DOI names in one defined area, as a value-added feature. These may be a paid for service or free to all users. For an example, see CrossRef free DOI lookup.

4. How many DOI names are there, and who uses them?

Almost 60 million DOIs have been assigned through a federation of Registration Agencies world-wide. See the factsheet DOI Key Facts and the DOI Handbook, 2 Numbering.

5. Can the DOI system use, or work with, existing identifier schemes?

Yes. See the DOI Handbook, 2 Numbering, for more information.

6. What can a DOI name be assigned to?

It can be any entity — physical, digital or abstract — that you wish to identify, primarily for sharing with an interested user community or managing as intellectual property.

7. If I have assigned a DOI name and I make a change to my material, should I assign a new DOI?

The IDF does not have any rules on this. Individual RAs adopt appropriate rules for their community and application. As a general rule, if the change is substantial and/or it is necessary to identify both the original and the changed material, assign a new DOI name.

8. Is the DOI system a standard?

Yes. The DOI system was created by the International DOI Foundation and has been adopted as an International Standard, ISO 26324. The IDF is the ISO 26324 Registration Authority. Compliance with the DOI Handbook ensures compliance with the ISO 26324 standard.

9. What is a shortDOI?

A shortDOI^® is a shortcut to a DOI name. It provides a function similar to that which URL shortening services do for URLs. shortDOIs are not themselves DOI names.

10. How does the DOI system differ from the Handle System?

The DOI system implements the Handle System and adds to it some other features.

11. DOI & URI: how does the DOI system work with web URI technologies?

DOI names may be expressed as URLs (URIs) through a HTTP proxy server. In addition, DOI is a registered URI within the info-URI namespace (IETF RFC 4452, the "info" URI Scheme for Information Assets with Identifiers in Public Namespaces). See the DOI Handbook, 2 Numbering and 3 Resolution, for more information.

Updated May 2012     |     DOI®, DOI.ORG®, doi>® and shortDOI® are trademarks of the International DOI Foundation.