# Email DNS Preflight

> 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.

## Facts

- Endpoint: GET https://email-dns-preflight-x402.copper-crate.workers.dev/v1/email/preflight?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/email-dns-preflight-3c6db3ee
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_WI-uKAcwoBjYHLs2y5wEE

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability email-dns-preflight-3c6db3ee
```

Example prompt: Can you preflight the email address alice@acmecorp.com and tell me whether the syntax is clean, whether the domain has MX records, and what SPF and DMARC policies are in place — without actually sending anything?

## When to prefer this

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.

## Known failure modes

- 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

## 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.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "email"
     ],
     "properties": {
      "email": {
       "type": "string",
       "maxLength": 254,
       "description": "Email address to preflight via the email query parameter."
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "email",
      "domain",
      "mailRoute",
      "authentication",
      "score",
      "mailbox"
     ],
     "properties": {
      "email": {
       "type": "string"
      },
      "score": {
       "type": "number"
      },
      "domain": {
       "type": "string"
      },
      "mailbox": {
       "type": "object"
      },
      "mailRoute": {
       "type": "object"
      },
      "authentication": {
       "type": "object"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "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"
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/email-dns-preflight-3c6db3ee/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from email-dns-preflight-x402.copper-crate.workers.dev](https://www.zero.xyz/host/email-dns-preflight-x402.copper-crate.workers.dev/llms.txt)