Direct comparison
DOI vs. URL: Which to Cite?
A URL is a temporary web address; a DOI is a persistent, registered identifier that survives link changes. Compares persistence, resolution, citation use.
Side-by-side comparison
| Dimension | DOI | URL |
|---|---|---|
| What it identifies | A registered digital object (article, dataset, software, etc.) | A current location on a specific server |
| Persistence guarantee | Formal commitment by the registrant to keep it resolving | None — works only as long as that exact address is live |
| Assigning / governing body | Accredited Registration Agencies (Crossref, DataCite, etc.) under the International DOI Foundation; ISO 26324 | None — anyone with server access can create or delete one |
| Format | Prefix/suffix string, e.g. 10.1038/nature14539 | Full web address, e.g. https://example.edu/files/report.pdf |
| Resolution mechanism | Handle System via the doi.org resolver, redirecting to the current target URL | Direct HTTP request to the exact address encoded in the string |
| What happens if content moves | Registrant updates the target URL; the DOI keeps resolving correctly | The link breaks — no mechanism connects the old address to the new one |
| What happens if content is removed | Can resolve to a DOI tombstone page explaining the removal/retraction | Typically a dead link (404) with no explanation |
| Cost to obtain | Paid, opt-in registration by a publisher or repository | Free — exists automatically wherever content is hosted |
| Recommended for citation when | Always, when one has been assigned to the resource | Only as a fallback when no DOI exists, ideally with an access date |
Common questions
FAQ
If a resource has both a DOI and a URL, which should I cite?+
Cite the DOI. It is the identifier citation managers, ORCID, CRIS/RIM systems, and funder reporting platforms expect, and it will keep resolving even if the URL later changes.
Does a DOI link ever change?+
The DOI string itself does not change, but the URL it resolves to can be updated by the registrant behind the scenes — that indirection is the entire point of using a DOI instead of citing the URL directly.
Is it ever acceptable to cite a bare URL?+
Yes, when no DOI has been assigned to the resource — for example many web pages, internal reports, or older content. Most style guides recommend including an access date in that case, since there is no persistence guarantee behind the link.
Why does a DOI cost money when a URL is free?+
The fee funds the Registration Agency’s ongoing obligation to maintain resolvable metadata and target-URL updates for the life of the object — a URL carries no such maintenance commitment from anyone.
