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SiteSignal Crossref DOI Metadata
x402
SiteSignal Crossref DOI Metadata is a paid API for AI agents from phases-prot-shine-royal.trycloudflare.com, paid per call via x402, $0.01/call, status down (last checked 2026-09-15).
Returns bibliographic, authorship, publication, subject, funding, license, and citation-count metadata for a given DOI via the Crossref registry.
Price / call$0.01
Success—
StatusDown
How this service works
Return bounded bibliographic, authorship, publication, subject, funding, license, and citation-count metadata for one DOI from Crossref.
Output
A structured JSON object containing bounded bibliographic metadata from Crossref, including: title, authors, publication venue, publication date, subject classifications, funding acknowledgements, license information, and citation count for the requested DOI.
Example use cases
Enrich research paper database
“I have a list of DOIs for papers we've cited in our report — can you fetch the full Crossref metadata for DOI 10.1126/science.aaf3777, including authors, journal name, publication date, and citation count?”
Verify funder and license for open access
“Can you check the funding sources and license terms for the article with DOI 10.1371/journal.pmed.1003763 so I know if it's openly licensed and who paid for the research?”
Identify co-authors of a paper
“Who are the authors of the paper with DOI 10.1016/j.cell.2020.08.001, and what journal and year was it published in?”
Technical details
Endpoint
GEThttps://phases-prot-shine-royal.trycloudflare.com/x402/doi-metadataWhen to prefer
Choose this endpoint when you need structured, authoritative bibliographic metadata for a specific scholarly DOI, including citation counts, funding, licensing, and authorship — sourced directly from the Crossref registry. Prefer this over general web scraping or other DOI resolvers when you need machine-readable, normalized academic metadata rather than a rendered landing page.
Side effects
- DOI not found in Crossref registry — returns empty or error response
- Malformed DOI string (e.g. includes full doi.org URL prefix instead of bare DOI) — rejected by schema validation
- Crossref rate limiting or upstream downtime — may return timeout or 5xx error
- DOI exists but has incomplete metadata — some fields may be null or absent
- Non-scholarly DOIs (e.g. for datasets or grey literature) may have sparse metadata
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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