Email validate

Validate an email address: syntax check plus live MX record lookup on the domain (deliverability signal, not a guarantee).

Input

Example output

{
  "email": "ada@example.com",
  "syntaxValid": true,
  "domain": "example.com",
  "mxRecords": [
    "mail.example.com"
  ],
  "deliverableDomain": true
}

Try it - see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/email-validate \
  -H "Content-Type: application/json" \
  -d '{"email":"ada@example.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-validate", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "email": "ada@example.com"
  }),
});

Part of these workflows

This tool is one step in 3 curated multi-tool workflows - agents can fetch the whole sequence as an MCP prompt or call https://agent402.tools/api/skill-packs/{slug}/prompt.

• 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.
• User onboarding - Take a signup form submission and run the full onboarding workup deterministically: validate the email, score the chosen password, mint a stable internal ID, derive a URL-safe handle from the display name, generate a recovery / API secret, hash the password for storage, and verify the 2FA setup code. One pass, every step a pure-CPU call.
• Contact verification - Verify an email address is deliverable - syntax validation plus MX record check on the domain.

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