DMARC check

Fetch and validate a domain's DMARC policy at _dmarc.<domain> (RFC 7489). Send POST /api/dmarc-check with the required field domain and pay $0.001 per call over x402 or MPP (there is no free tier). It returns a JSON object with domain, hasRecord, raw, policy, subdomainPolicy and 5 more.

Surfaces the enforcement policy (none/quarantine/reject), reporting addresses, alignment modes, and common misconfigs (no rua, p=none stuck for months, percent <100). Pair with SPF and DKIM for full Feb-2024 sender-rule compliance.

Category: Network & domains · Tags: dmarc email email-auth deliverability dns rfc7489

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Parameters

Example request

curl -i -X POST https://agent402.tools/api/dmarc-check \
  -H "Content-Type: application/json" \
  -d '{"domain":"google.com"}'

Without payment this returns HTTP 402 Payment Required with the exact price for dmarc-check; any x402 v2 or MPP client pays it and retries.

Example response

{
  "domain": "google.com",
  "hasRecord": true,
  "raw": "v=DMARC1; p=reject; rua=mailto:mailauth-reports@google.com",
  "policy": "reject",
  "subdomainPolicy": "reject",
  "percent": 100,
  "alignment": {
    "spf": "r",
    "dkim": "r"
  },
  "reportingUris": {
    "aggregate": [
      "mailto:mailauth-reports@google.com"
    ],
    "failure": []
  },
  "valid": true,
  "warnings": []
}

From an MCP client

catalog.call {
  "slug": "dmarc-check",
  "params": {
    "domain": "google.com"
  }
}

The hosted connector at https://agent402.tools/mcp needs a payment for dmarc-check; the stdio package pays it from a wallet or from AGENT402_CREDITS_KEY. Local install: npx -y agent402-mcp.

Errors and behavior

• domain is required. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example, so the caller can correct it.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Wallet-only: this tool reaches the network or stored state, so it has no proof-of-work tier. A prepaid card-credits key issued earlier (Authorization: Bearer a402_...) also pays it.
• A GET or HEAD to /api/dmarc-check returns the same 402 quote, so the price can be read without a body.
• An Idempotency-Key header makes a retried paid call replay the first 200 instead of charging again (an answer larger than 1 MB is not replayed).

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
client.setSpendControls?.(false); // keep your own spending ceiling in code
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/dmarc-check", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "domain": "google.com"
  }),
});

Part of these workflows

DMARC check is one step in these 3 skill packs, each sold as a single call:

• Security audit - Enumerate a domain's external attack surface in one workflow: certs, DNS posture, email auth, HTTP security headers, and tech stack.
• Email deliverability - Diagnose why a domain's email lands in spam: SPF posture, DMARC policy, DKIM key strength, MX targets, and a composite 0–100 score.
• Email security - Full email auth posture: SPF, DMARC, DKIM, and composite deliverability score in one call.

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