What Is a DOI? How to Verify a DOI Number
A DOI (Digital Object Identifier) is a unique identifier permanently assigned to an academic publication. Even if the journal's site moves or its address changes, the DOI stays the same and always leads to the publication. This article explains the structure of a DOI and how to check whether one is real.
What does a DOI look like?
A typical DOI looks like this:
10.1038/s41586-021-03819-2- 10. — every DOI starts with this prefix.
- 1038 — the registrant's number (here, the publisher Nature).
- s41586-021-03819-2 — the publication-specific suffix.
A DOI is usually written as a link: https://doi.org/10.1038/s41586-021-03819-2. Most citation styles, including APA 7, ask for the DOI in this form.
How to verify a DOI
- Resolve it through doi.org. Append the DOI to
https://doi.org/and open it in your browser. A real DOI takes you to the publication's page; a fake one returns a “DOI not found” error. - Compare the opened page with the citation. Even if the DOI resolves, watch out: AI sometimes pastes another article's real DOI onto a fabricated citation. The title, authors and year on the opened page must match your bibliography exactly.
- Search CrossRef. At
search.crossref.orgyou can search by the article title and see the registered DOI.
Does every publication have a DOI?
No. Older publications, some national journals, books, theses and conference papers may not carry a DOI. A source without a DOI is not automatically fake; in that case you should verify it through the journal archive, Google Scholar or library catalogs.
Checking all DOIs in a bibliography at once
Opening every DOI in a long bibliography by hand is impractical. The Citation Checker toolresolves all DOIs in your bibliography automatically, compares the resolved record's title/author/year with your citation and flags mismatches. For sources without a DOI, it searches for a title match across CrossRef, OpenAlex, PubMed and Semantic Scholar.