{"data":{"slug":"crossref","name":"Crossref","homepage":"https://www.crossref.org/","record_types":["scholarly_works"],"places":["global"],"years":null,"access_method":"api","api_docs_url":"https://www.crossref.org/documentation/retrieve-metadata/rest-api/","terms_url":"https://www.crossref.org/documentation/retrieve-metadata/rest-api/access-and-authentication/","robots_ok":null,"rate_limit":"Public pool: rate 5, concurrency 1. Polite pool (a mailto parameter or contact in the User-Agent): rate 10, concurrency 3. The API answers with x-rate-limit-limit and x-rate-limit-interval headers (3 per 1 s on the polite pool when checked).","key_required":false,"key_env":null,"review":"verified","verified_at":"2026-11-02","evidence":["https://www.crossref.org/documentation/retrieve-metadata/rest-api/","https://www.crossref.org/documentation/retrieve-metadata/rest-api/access-and-authentication/","https://www.crossref.org/documentation/retrieve-metadata/rest-api/tips-for-using-the-crossref-rest-api/"],"notes":"DOI metadata for journal articles, books and dissertations, with author affiliations where the publisher deposited them. No key. Lineage joins the polite pool by sending mailto (LINEAGE_CONTACT_EMAIL) as a parameter and in the User-Agent, spaces calls 400 ms apart per instance, caches responses 6 hours as the tips page asks, and backs off on 429. Crossref treats bibliographic metadata as facts with no reuse restriction; abstracts can carry the publisher's copyright, so Lineage does not request them. api.crossref.org serves no robots.txt (404).","status":"live","key_configured":null,"health":{"status":"live","checked_at":"2026-11-03T03:51:18.323Z","http_status":200,"latency_ms":745,"probe_url":"https://api.crossref.org/works?rows=0","reason":null},"links":{"self":"https://api.lineage.rexstjohn.com/v1/sources/crossref","page":"https://api.lineage.rexstjohn.com/sources/crossref","llms_txt":"https://api.lineage.rexstjohn.com/sources/crossref/llms.txt"}},"checked_at":"2026-11-03T03:51:18.323Z"}