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Email DNS Preflight
x402
Email DNS Preflight is a paid API for AI agents from email-dns-preflight-x402.copper-crate.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-15).
Validates email address syntax and checks public DNS/mail infrastructure posture (MX, SPF, DMARC) without performing SMTP mailbox verification.
Price / call$0.001
Success—
StatusUnknown
How this service works
Pay-per-call email syntax and public DNS/mail posture preflight. No mailbox-level SMTP claim.
Output
Returns a JSON object containing: a numeric deliverability score (0–100), parsed syntax profile (practical-ascii or similar) with accepted/roleBased flags, mail route assessment (hasMx, nullMx, verdict string), and DNS authentication posture for both SPF (present/missing status) and DMARC (policy type + status). Does not include SMTP-level mailbox existence verification.
Example use cases
Pre-send deliverability check for newsletter signup
“Before we add bob@startup.io to our mailing list, can you check whether that email address has valid syntax, a configured mail route, and passing SPF and DMARC records — I want to know if it's safe to send to without actually pinging the mailbox.”
Fraud screening on new user registration
“A new user just signed up with the email noreply@suspiciousdomain.biz — can you run a preflight on it and tell me if it's a role-based address, whether the domain has MX records, and what its overall deliverability score looks like?”
B2B outreach domain health audit
“I'm about to start cold outreach to leads at techcorp.com — can you check whether that domain has proper MX, SPF, and DMARC authentication set up so I know my emails won't bounce or get flagged as unauthenticated?”
Technical details
Endpoint
GEThttps://email-dns-preflight-x402.copper-crate.workers.dev/v1/email/preflight?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need lightweight, pay-per-call email validation that goes beyond pure regex syntax checking to include real DNS infrastructure signals (MX, SPF, DMARC) but explicitly does not require or perform SMTP mailbox-level probing. Ideal for pre-send preflight checks, registration form validation, and lead scoring pipelines where SMTP probing is too slow, blocked, or legally inadvisable.
Side effects
- Invalid or malformed email address input returns a syntax rejection with accepted:false
- Domain with no DNS resolution may return hasMx:false and a degraded score
- Rate limits or payment failures return 402 or 429 status codes
- Transient DNS lookup failures may produce incomplete authentication fields
- Extremely new domains may lack SPF/DMARC records, returning status:missing for those fields
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"email": "alice@example.com",
"score": 95,
"domain": "example.com",
"syntax": {
"profile": "practical-ascii",
"accepted": true,
"roleBased": false
},
"mailbox": {
"smtpVerified": false,
"deliverabilityClaimed": false
},
"mailRoute": {
"hasMx": true,
"nullMx": false,
"verdict": "mail_route_configured"
},
"authentication": {
"spf": {
"status": "present"
},
"dmarc": {
"policy": "reject",
"status": "present"
}
}
}
}Tags
x402
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