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Email Address MX Verify
x402
Email Address MX Verify is a paid API for AI agents from sdn-screen-x402.sdnscreen.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-13).
Verifies whether an email address domain is deliverable by performing DNS-based MX record lookup and checking for disposable, role-based, or unresolvable mail hosts
Price / call$0.01
Success—
StatusUnknown
How this service works
Six keyless pay-per-call tools for AI agents: OFAC SDN crypto-wallet screen, live DNS records lookup, SPF/DMARC/DKIM email-auth check, domain age/registrar (RDAP), email address MX verify and URL unshorten/redirect check. $0.01 per call: USDC on Base over x402, or USDC on Tempo over MPP. Also a remote MCP server at /mcp (x402).
Output
Returns a JSON object with a verdict enum (deliverable_domain, risky, undeliverable, unknown), a list of MX records (host and priority), boolean flags for acceptsMail, disposable, roleAccount, freeProvider, nullMx, implicitMx, syntaxValid, domainExists, and mxHostResolves, plus a reasons array listing specific failure codes (e.g. null_mx, no_mx_or_a, disposable_domain), the resolver used (Cloudflare 1.1.1.1 over DoH), and a checkedAt timestamp. Note: DNS-only — no SMTP connection is made and no mail is sent.
Example use cases
Pre-send email deliverability check
“Before I send my newsletter campaign, can you check whether subscriber@outlook.com has a real, deliverable domain with working MX records and isn't a throwaway address?”
Onboarding form email fraud detection
“A new user just signed up with the email noreply@tempmail.org — can you check if it's a disposable or role-based address that I should block from registering?”
CRM contact data hygiene
“I need to clean up my CRM — can you verify whether the email address sales@startupxyz.co has valid MX records and is actually set up to receive mail?”
Technical details
Endpoint
GEThttps://sdn-screen-x402.sdnscreen.workers.dev/v1/mx-verify?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a fast, keyless, pay-per-call DNS-level email deliverability check without sending any test email or making SMTP connections. It is ideal for agent workflows that need to screen email addresses at onboarding, in CRM hygiene pipelines, or pre-send validation, especially when you also need disposable/role-account flagging in the same call. Prefer alternatives (SMTP-level validators) only when you need to confirm individual mailbox existence beyond the domain level.
Side effects
- Email address missing or malformed — returns 400 with validation error
- Domain does not exist (NXDOMAIN) — verdict is undeliverable, reasons includes domain_nxdomain
- Domain has null MX record — verdict is undeliverable, reasons includes null_mx
- MX hosts listed but unresolvable — verdict is risky, reasons includes mx_host_unresolvable
- DNS lookup error (upstream failure) — verdict is unknown, reasons includes dns_error
- Payment not provided or invalid x402/MPP credential — returns 402 Payment Required
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"mx": [
{
"host": "gmail-smtp-in.l.google.com",
"priority": 5
},
{
"host": "alt1.gmail-smtp-in.l.google.com",
"priority": 10
}
],
"note": "DNS-only check: no SMTP connection and no mail sent, so it cannot confirm the individual mailbox exists. deliverable_domain = the domain is set up to receive mail.",
"email": "someone@gmail.com",
"domain": "gmail.com",
"nullMx": false,
"reasons": [],
"verdict": "deliverable_domain",
"resolver": "Cloudflare 1.1.1.1 (DNS over HTTPS)",
"checkedAt": "2026-10-12T17:50:00.000Z",
"disposable": false,
"implicitMx": false,
"acceptsMail": true,
"roleAccount": false,
"syntaxValid": true,
"domainExists": true,
"freeProvider": true,
"mxHostResolves": true
}
}Tags
x402
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