How to tell a fabricated DOI from a real one

The single fastest check on any reference that carries one.

A DOI is a permanent identifier assigned to a work by a registration agency when it is published. It looks like 10.1086/225469: a prefix beginning 10. that identifies the registrant, a slash, and a suffix the publisher chooses. Because it is assigned centrally rather than derived from the work, a DOI cannot be inferred, guessed, or reconstructed. Either it was registered or it was not.

That property is what makes it the strongest test available. A language model producing a citation can imitate a title, an author list, and a volume number, because those follow patterns. It cannot produce a registered identifier for a work nobody registered.

How to resolve one

Paste the DOI after https://doi.org/ and open it. Three outcomes:

It lands on the publisher's page for that exact work. The reference exists. You still want to confirm the title and authors match what you wrote.
"DOI Not Found." No registration agency has this identifier. On a citation that otherwise looks polished, this is the fabrication pattern.
It lands on a different paper. The citation was assembled from parts, or a digit was mistyped. Compare the resolved title against the one you have before assuming either.

Two traps

A well-formed DOI is not a real DOI. 10.1016/j.jbusres.2021.99999 has the correct shape and a real publisher prefix, and resolves to nothing. Shape tells you the string is syntactically valid, which is a different and much weaker claim.

A resolving DOI does not confirm the rest of the citation. The identifier points at one specific work. If the year, volume, or author list in your reference disagrees with the page it opens, the reference is still wrong, and a reviewer will find that as easily as you just did.

When there is no DOI

Books, older articles, working papers, and conference proceedings often carry none, and their absence proves nothing. Fall back to the title, author, and container checks.

The shortcut: paste your bibliography into CiteFact and every entry is checked against CrossRef and OpenAlex at once, retractions included. Free for 10 references, no signup.