DKIM key lookup

Fetch and parse a DKIM public-key record at <selector>._domainkey.<domain> (RFC 6376). Send POST /api/dkim-lookup with the required fields domain and selector and pay $0.002 per call over x402 or MPP (there is no free tier). It returns a JSON object with domain, selector, fullName, hasRecord, raw and 7 more.

Returns the parsed key params (algorithm, length, flags) so you can verify rotation status or key strength. Caller must know the selector - use email-deliverability if you don't.

Category: Network & domains · Tags: dkim email email-auth deliverability dns rfc6376

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Parameters

Example request

curl -i -X POST https://agent402.tools/api/dkim-lookup \
  -H "Content-Type: application/json" \
  -d '{"domain":"google.com","selector":"20221208"}'

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

Example response

{
  "domain": "google.com",
  "selector": "20221208",
  "fullName": "20221208._domainkey.google.com",
  "hasRecord": true,
  "raw": "v=DKIM1; k=rsa; p=MIIBIj...",
  "version": "DKIM1",
  "keyType": "rsa",
  "hashAlgorithms": [],
  "serviceType": "*",
  "flags": [],
  "publicKey": {
    "base64": "MIIBIj...",
    "bits": 2048,
    "revoked": false
  },
  "warnings": []
}

From an MCP client

catalog.call {
  "slug": "dkim-lookup",
  "params": {
    "domain": "google.com",
    "selector": "20221208"
  }
}

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

Errors and behavior

• domain and selector are 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/dkim-lookup 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/dkim-lookup", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "domain": "google.com",
    "selector": "20221208"
  }),
});

Part of these workflows

DKIM key lookup is one step in these 2 skill packs, each sold as a single call:

• 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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