Unpaywall

Science & MathCA

api.unpaywall.org

Unpaywall, by OurResearch, resolves a DOI to its open-access status and legal full-text links: whether any OA copy exists, its oa_status (gold, hybrid, bronze, green or closed), the best OA location with PDF and landing-page URLs, every known OA location with host type and licence, journal and publisher metadata.

Runs on your machine under the source's own terms

The crw MCP on your computer calls Unpaywall directly. Calls cost no credits and the data does not pass through fastCRW. Install it once for Claude Code, Cursor, Codex, Windsurf, Gemini CLI or OpenCode, with your fastCRW API key in place of the placeholder:

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Capabilities (1)

unpaywall/doiFree, runs locally

Returns one DOI's open-access verdict: is_oa, oa_status, the best OA location with PDF and landing URLs, every OA location with host type, version, licence and repository, plus title, year, journal, publisher and the DOI's canonical URL.

doiemail

Licence

Any unauthorized use, reproduction, modification, distribution or republication of the Data or Database without Impactstory's prior written consent is strictly prohibited.

https://unpaywall.org/legal/terms-of-service

Attribution

Display this wherever you show the data. It arrives on every response as provenance.attributionText.

Open-access data from Unpaywall (unpaywall.org), a service of OurResearch. Not affiliated with or endorsed by OurResearch.

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