Does this need an API key?

No. It queries the public Crossref REST API at api.crossref.org, which is keyless and free. Only the work's bibliographic metadata is fetched — no account or token is required.

Which styles are supported?

APA 7th, MLA 9th, Chicago author-date, IEEE, Harvard, and BibTeX. The citation is built from the Crossref metadata (authors, title, container, volume, issue, pages, year, DOI) using the rules for each style.

What if the DOI is not found?

If Crossref returns a 404 or no metadata, the tool shows a clear error. Double-check the DOI for typos — DOIs are case-insensitive but must be complete, starting with the 10. prefix.

Does my DOI get logged anywhere by this tool?

The tool itself stores nothing; the lookup is a direct browser request to Crossref. Crossref's own API may rate-limit by IP, but no Gera server sees your query.

Why does the author list sometimes look incomplete?

Crossref metadata occasionally omits given names or lists organisations as authors. The formatter renders whatever names Crossref provides and falls back gracefully when a name part is missing.

DOI to Citation Formatter

Turn a DOI into a formatted citation

Paste a DOI and this tool fetches the article’s metadata from Crossref — the registry behind most journal DOIs — and formats a citation in your chosen style. It saves you from copying author lists and page numbers by hand, and it works for any DOI registered with Crossref.

How it works

The DOI is normalised (the https://doi.org/ prefix is stripped) and sent to the keyless Crossref REST endpoint https://api.crossref.org/works/{doi}. The JSON response contains structured metadata: author (an array of family/given names), title, container-title (the journal), volume, issue, page, the issued date-parts, and the DOI itself.

The formatter then assembles a citation per style. APA uses Author, A. B. (Year). Title. Journal, Vol(Issue), pages. https://doi.org/DOI. MLA puts the title in quotes and italicises the journal. Chicago author-date and Harvard are close variants. IEEE uses numbered initials, and BibTeX produces an @article entry. Everything runs in your browser — only the metadata request leaves your device.

Notes

Crossref is the right source for journal articles and conference papers. Books and datasets registered with other agencies (DataCite, mEDRA) may not resolve here. If a lookup fails, verify the DOI starts with 10. and contains no stray spaces.