# Kit Rx Domain WHOIS, DNS & Email Security

> Domain intelligence for AI agents: WHOIS (RDAP), DNS, SPF/DKIM/DMARC email security, bulk checks and due-diligence scores, paid per call over x402.

Domain registration facts from registry RDAP (registrar, created, expires, status), live DNS records, email authentication grading (MX, SPF walk, DMARC, MTA-STS, BIMI), bulk domain checks, email address validation, and a domain due-diligence risk report. Each call is one x402 v2 payment in USDC on Base, Polygon, Arbitrum, Avalanche or Sei; no signup or API key. Requests that fail or match nothing are not charged.

## Payment

- Protocol: x402 v2, scheme exact, USDC on Base (eip155:8453); also accepted: eip155:137,eip155:42161,eip155:43114,eip155:1329 (Polygon, Arbitrum, Avalanche, Sei). payTo 0xAf8E0A8a8A0A8f65831b2dD0FFe0c1B804698D70
- An unpaid request returns HTTP 402 with the payment requirements in the PAYMENT-REQUIRED header.
- Only 2xx responses are settled. 400 (invalid input), 404 (no match) and 5xx (upstream down) are free.
- A request with no query parameters runs the documented example query and says so in notes (defaulted_to_example: true).
- Machine-readable: https://domain.kit-rx.com/openapi.json, https://domain.kit-rx.com/.well-known/x402, https://domain.kit-rx.com/catalog.json
- MCP: remote Streamable HTTP server at https://domain.kit-rx.com/mcp (MCP Registry name com.kit-rx.api/kitrx). Each route is a tool; paid tools use the x402 MCP transport (_meta["x402/payment"]); kitrx_catalog is free.
- Human docs: https://domain.kit-rx.com/docs (one page per endpoint). Agent skill: https://domain.kit-rx.com/.well-known/agent-skills/index.json

## Endpoints

- GET https://domain.kit-rx.com/v1/domain/report ($0.01) params: domain. Due-diligence report on a website, merchant or counterparty domain: registrable domain, registry RDAP facts (registrar, abuse contact, created, expiry, age, status, nameservers), DNS records (A, AAAA, MX, NS, TXT, CAA) from Cloudflare DNS over HTTPS, SPF and DMARC posture, a live web probe (redirect chain, HTTPS, HSTS, site-supplied title, parked or for-sale signs), brand-impersonation checks, and a 0-100 risk score with transparent weighted signals and a verdict.
- GET https://domain.kit-rx.com/v1/domain/whois ($0.003) params: domain. Registration facts for a domain from its registry's RDAP server, located through the IANA bootstrap file: registrar name, IANA ID and abuse contact, created, updated and expiry dates, age and days to expiry, EPP status codes, transfer lock, nameservers, DNSSEC delegation flag, and the registry RDAP URL and terms link. No registrant contact data. Registries whose terms bar reuse (Nominet, CentralNic, Google Registry) are not queried.
- GET https://domain.kit-rx.com/v1/domain/dns ($0.003) params: domain, type?. Current DNS records for a hostname from Cloudflare DNS over HTTPS: A, AAAA, CNAME chain, MX with priority and null-MX flag, NS, TXT (up to 25 records of at most 400 characters, email addresses redacted), CAA as flag, tag and value, and SOA primary nameserver, serial and timers, each with its minimum TTL. An optional type parameter limits the answer to one record type. For subdomains without their own zone, NS and SOA come from the registrable domain.
- GET https://domain.kit-rx.com/v1/domain/email-auth ($0.003) params: domain. Email authentication posture of a domain from DNS (Cloudflare DNS over HTTPS): MX records and null MX, SPF parsed into mechanisms with its all qualifier and a recursive DNS-lookup count against the RFC 7208 limit of 10, DMARC policy (p, sp, pct, alignment, report addresses' domains), MTA-STS and TLS-RPT records, and BIMI. DKIM is not assessed because selectors cannot be enumerated. Returns an A-F grade and 0-100 score with weighted reasons.
- GET https://domain.kit-rx.com/v1/email/verify ($0.003) params: email. Checks an email address without sending mail: syntax rules (IDN domains in punycode and Unicode), MX records by preference, null MX (RFC 7505), implicit A/AAAA fallback, NXDOMAIN, SPF and DMARC policy, disposable, role, free-webmail and +tag flags, mail provider from MX hosts, and typo suggestions for popular domains. Returns a verdict and 0-100 score with reasons. Mailbox existence is not confirmed. Sources: Cloudflare DNS over HTTPS, disposable-email-domains (CC0).

## Data sources

US FDA (openFDA), NLM RxNav/RxNorm, CMS NADAC (data.medicaid.gov), Wikidata, GLEIF, SEC EDGAR, US Census Geocoder, USGS EPQS, NOAA NWS, RDAP registries, Cloudflare DNS-over-HTTPS, and the checked websites themselves. Reports are informational summaries; verify critical decisions against the primary source.