Transparency

Data sources

Every provider CitationCheck queries, what it covers well, and where it falls short. Querying a public API is not a partnership, and no provider endorses this service.

Crossref

Used for: DOI registration metadata for most journal articles, books, chapters, and conference papers registered with Crossref.
Limitations: Covers works registered with Crossref. Preprints, theses, reports, and some regional publishers may be missing or sparsely described.
Relationship: CitationCheck queries this provider's public API. There is no partnership, sponsorship, or endorsement.
Query data: Bibliographic details or identifiers from your citation are sent to this provider as search or lookup queries.
Documentation: Provider documentation
Last verified: 2026-08-07

OpenAlex

Used for: Broad open catalog of scholarly works, including many items without Crossref DOIs.
Limitations: Metadata is aggregated and occasionally lags or conflicts with publisher records.
Relationship: CitationCheck queries this provider's public API. There is no partnership, sponsorship, or endorsement.
Query data: Bibliographic details or identifiers from your citation are sent to this provider as search or lookup queries.
Documentation: Provider documentation
Last verified: 2026-08-07

arXiv

Used for: arXiv preprints in physics, mathematics, computer science, and related fields.
Limitations: Preprints only. A published journal version may differ from the arXiv record.
Relationship: CitationCheck queries this provider's public API. There is no partnership, sponsorship, or endorsement.
Query data: Bibliographic details or identifiers from your citation are sent to this provider as search or lookup queries.
Documentation: Provider documentation
Last verified: 2026-08-07

PubMed (NCBI E-utilities)

Used for: Biomedical and life-science literature indexed in PubMed (PMID resolution).
Limitations: Biomedical scope only. Used for PMID resolution, not general fuzzy search.
Relationship: CitationCheck queries this provider's public API. There is no partnership, sponsorship, or endorsement.
Query data: Bibliographic details or identifiers from your citation are sent to this provider as search or lookup queries.
Documentation: Provider documentation
Last verified: 2026-08-07

What this list does not include

CitationCheck does not scrape Google Scholar, does not access sources whose terms prohibit this use, and does not claim to search "the entire academic internet." If a discipline you work in is poorly covered by the providers above, results for that discipline will be weaker — and the honest answer is to check the source directly.

To check a citation, its bibliographic details (or identifier) are sent as queries to the enabled scholarly metadata providers listed on the Data Sources page. See the privacy page for the full picture.

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