dnsdoctor 🩺

Will email from a domain reach the inbox — or the spam folder? dnsdoctor does a live SPF / DKIM / DMARC / MX check for any domain and returns a HEALTHY / NEEDS_ATTENTION / AT_RISK verdict with the exact DNS records to add or fix.

It is both an MCP server (for Claude, Cursor and other AI agents) and a pay-per-call x402 HTTP API.

Why it exists: an AI agent setting up email, debugging "my mail goes to spam", or vetting a domain cannot resolve live DNS by itself. dnsdoctor does, and turns it into an actionable answer — including the Gmail/Yahoo 2024 bulk-sender requirements (DMARC).

MCP server (free)

{
  "mcpServers": {
    "dnsdoctor": { "command": "npx", "args": ["-y", "dnsdoctor-mcp"] }
  }
}

Tool: check_email_deliverability(domain, deep?).

Related MCP server: HeaderHawk

Free HTTP API

GET https://dnsdoctor.vercel.app/check?domain=github.com

Returns SPF/DMARC/MX status, a deliverability score and concrete fixes. Rate-limited to 30/hour/IP.

Pay-per-call (x402)

GET https://dnsdoctor.vercel.app/pro/check?domain=<domain>

Gated by x402: your agent pays $0.02 USDC (on Base) per call automatically — no sign-up, no API key. The deep tier also probes common DKIM selectors. The server holds no private key; payment settles on-chain to the operator wallet.

What it checks

Develop

npm install
npm run dev:http     # local HTTP API on :8080
npm test             # live engine tests

MIT.