Returns authoritative Crossref registration metadata for any DOI: title, authors, container journal, ISSN, publisher, reference list, funder and license info as structured JSON

Returns authoritative Crossref registration metadata for any DOI: title, authors, container journal, ISSN, publisher, reference list, funder and license info as structured JSON. A core keyless enrichment endpoint for autonomous research agents and agent-to-agent citation-verification and bibliographic pipelines. First 3 calls FREE per wallet — send header X-WALLET: 0x<addr>. No charge on upstream failure.