Email deliverability check

End-to-end email-auth report for a domain: SPF + DMARC + DKIM (probes common selectors automatically) + MX records + score 0–100. The one call to make when 'why is our mail going to spam?' lands in your inbox.

Input

Field	Type	Description
domain *	string	Domain name (also accepts email/url/host)
dkimSelectors	array	Optional DKIM selectors to probe (overrides default list of 14 common selectors)

Example output

{
  "domain": "google.com",
  "score": 90,
  "summary": "good",
  "spf": {
    "hasRecord": true,
    "all": "softfail",
    "valid": true,
    "lookupCount": 1
  },
  "dmarc": {
    "hasRecord": true,
    "policy": "reject",
    "percent": 100,
    "valid": true
  },
  "dkim": {
    "found": [
      {
        "selector": "20221208",
        "bits": 2048,
        "valid": true
      }
    ],
    "probed": [
      "google",
      "selector1",
      "default",
      "20221208"
    ]
  },
  "mx": {
    "count": 5,
    "records": [
      "smtp.google.com"
    ]
  },
  "checks": [
    {
      "check": "spf",
      "status": "pass",
      "detail": "SPF record present, 1 DNS lookup, ~all qualifier"
    },
    {
      "check": "dmarc",
      "status": "pass",
      "detail": "p=reject at 100% — strict enforcement"
    },
    {
      "check": "dkim",
      "status": "pass",
      "detail": "Found DKIM at selector 20221208 (2048-bit RSA)"
    },
    {
      "check": "mx",
      "status": "pass",
      "detail": "5 MX records configured"
    }
  ],
  "queriedAt": "2026-06-19T20:00:00.000Z"
}

Try it — see the 402 challenge (free)

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

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

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();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

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

Wallet-only. This tool reaches the network/browser/storage, so it is paid in USDC via x402 (no proof-of-work tier).

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