Tools

Seven tools for working with Crossref data — DOI resolution, full-text search across all scholarly works, outgoing reference lists, and journal, funder, and publisher lookup:

crossref_get_work

Resolve a DOI to its canonical Crossref record.

• DOI validated against 10.NNNN/suffix regex before the upstream call
• Returns title, authors with affiliations, abstract (when deposited), container/journal, publication date, work type, ISSN, license URLs, full-text link URLs, and funder acknowledgements
• The author list is paged with offset and limit (default 25, max 500). authorCount is the full deposited total; when authors remain, the response carries a nextOffset to pass back as offset. Ordinary records fit in a single page — large-collaboration papers deposit thousands of authors, enough to fill a client's context from one record. Only the author list is paged; every other field comes back in full on every page.
• A funder or an affiliation the publisher asserted through the ROR registry rather than by name carries that identifier as ror, and no name. The entry still names an organization instead of coming back as an award number with nothing attached to it.
• A date component Crossref records as unknown — it deposits null in place of the number — is omitted rather than reported, so a record with no registered year comes back with no publication date.
• The publication date is the first of published, published-print, published-online, and issued that names one. The three search tools read the same order without issued, which is this tool's alone. A source deposited holding only unknown components names nothing and is passed over; one naming a coarser date than the source behind it still answers, since the four are different facts rather than one fact at four precisions.
• Outgoing references are reported as a count; the entries themselves come from crossref_get_references
• Incoming citation count (is-referenced-by-count) is included; citing works are not — Crossref does not expose that data. Use OpenAlex for citation graphs.

crossref_search_works

Search across ~155M Crossref-registered works.

• Free-text query plus a structured filter object using Crossref's hyphen-separated key syntax: from-pub-date, until-pub-date, type, funder, issn, member, has-abstract, has-references, has-full-text, directory (use DOAJ to restrict to open-access content)
• Field-specific query parameters scope matching beyond the generic query: queryTitle, queryAuthor, queryContainerTitle (journal/book name), and queryBibliographic (whole-citation match to resolve a known reference to its DOI) — all combine with each other and with query
• Sort by relevance, is-referenced-by-count, published, deposited, or score
• fields parameter narrows response payload — useful for large result sets. Names are case-sensitive; DOI is always returned whether or not it is listed, so every result stays resolvable by crossref_get_work.
• Each work returns at most authorLimit authors (default 25, max 500), with authorCount reporting that work's full deposited total. A single page of large-collaboration papers can carry tens of thousands of author entries; pass a cut work's DOI to crossref_get_work to page its whole author list, or raise authorLimit to widen the cap here.
• Offset paging up to ~10K results; deep paging requires cursor=* on the first call, then pass the returned nextCursor token. Cursor and offset cannot be combined.
• A cursor walk ends on the page that omits nextCursor. Crossref keeps minting a token past the end of a list, so the token is withheld on an empty page rather than relayed — the rule the works_cursor walks below follow too. Here that page also carries a notice saying the walk is complete, because works is this tool's whole payload and an empty page nothing is said about renders as blank text.

crossref_get_references

Fetch the outgoing reference list for a DOI.

• Each reference includes its deposited citation string and, where Crossref has resolved it, a DOI for follow-up lookup
• Citation strings come back with markup removed — inline emphasis (<i>, <em>, <small>, <span>), scripts (<sub>, <sup>, <inf>), block boundaries (<p>, <br>, <refersplit />), MathML and TeX formula wrappers, and a whole JATS <mixed-citation> deposited into a free-text field. A bracket comes out only when it is a well-formed tag whose element name is on a closed list, so an angle-bracket span that is not one — a cited URL, a Miller index, a DOI fragment, a bracketed phrase — is returned exactly as deposited. A link (<a>, <ext-link>, <uri>) is decided against its own text: its tags come out where the text already carries what the href holds, and stay where the href addresses something the text does not name.
• Paged with offset and limit (default 100, max 500). referenceCount is the full deposited total; when more remain, the response carries a nextOffset to pass back as offset. Most works fit in a single page — bibliography records can carry tens of thousands of references.
• Coverage varies by publisher — pre-2000 literature and non-participating publishers may have no reference list
• Single-hop only; agents that need N-hop traversal chain calls explicitly

crossref_search_journals

Find journal records by ISSN or title.