Infrastructure monitor for one domain (?domain=): DNS (nameservers, MX, CAA, DNSSEC DS, DMARC, apex addresses), HTTPS and the newest unexpired certificate in Certificate Transparency (issuer, expiry), redirects (http to https, www, the homepage's final address, HSTS), homepage structured data (blocks that do not parse, @type set, declared business name/phone/url) and declared agent capabilities (agent card, MCP server card, API catalog, skills index). Every domain on an active licence is re-read about every 4 hours; a change is reported only when two readings in a row agree. Returns the confirmed state, any change awaiting confirmation, and - for the licence holder or owner - the change history. Changes go into /api/v1/changes (section infrastructure), the stream and the licence webhook; medium and high changes are emailed. Signed (crawlcheck-infrastructure-monitor).