{
  "id": "crossref",
  "name": "Crossref",
  "category": "Research metadata",
  "summary": "Look up DOI metadata and search scholarly works.",
  "capabilities": [
    "doi.lookup",
    "scholarly.search"
  ],
  "auth": "none",
  "auth_basis": "Provider documentation says no sign-up is required; one anonymous DOI lookup also passed.",
  "docs": "https://www.crossref.org/documentation/retrieve-metadata/rest-api/",
  "endpoint": "https://api.crossref.org/works/{doi}",
  "method": "GET",
  "limits": [
    "Metadata availability varies by work; some abstracts have separate copyright restrictions.",
    "One DOI lookup does not verify completeness or search quality."
  ],
  "example": "https://api.crossref.org/works/10.1038%2Fnphys1170",
  "pricing": "Check current public/polite-pool usage guidance; this record is not a price quote.",
  "reviewed_at": "2026-10-17",
  "evidence": {
    "kind": "scoped_observation",
    "observation": {
      "service_id": "crossref",
      "observed_at": "2026-10-17T15:09:22.986238+00:00",
      "method": "GET",
      "url": "https://api.crossref.org/works/10.1038%2Fnphys1170",
      "assertion": "Return the requested DOI and a nonempty title",
      "scope": "One anonymous read-only request; no reliability, completeness, safety or future-availability guarantee.",
      "passed": true,
      "elapsed_ms": 312
    }
  },
  "constraints": {
    "retention_hours": null,
    "max_total_cost": null
  },
  "source_kind": "provider_documentation"
}