# Polyform Email Domain Deliverability Check

> Polyform Email Domain Deliverability Check is a paid API for AI agents from polyform.polyform-org.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-14).

Checks whether a domain can receive email by querying MX, SPF, and DMARC DNS records via DNS-over-HTTPS and returns a structured deliverability summary.

## Facts

- Endpoint: GET https://polyform.polyform-org.workers.dev/v1/email/domain-check
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/polyform-email-domain-deliverability-check-bac5c666
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sEFgnyi5NNHCPFBFnb0Vz

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 polyform-email-domain-deliverability-check-bac5c666
```

Example prompt: Can you check if acmecorp.com is properly set up to receive email — does it have MX records, and are SPF and DMARC configured correctly?

## When to prefer this

Choose this endpoint when you need a quick, structured assessment of whether a domain is configured to receive email, combining MX presence, SPF policy, and DMARC authentication in a single call. Ideal for pre-send validation, lead enrichment, fraud detection, or vendor onboarding workflows where you need to know if emailing a domain is likely to succeed and whether the domain operator takes email security seriously.

## Known failure modes

- Domain does not exist or is not registered — returns no records found
- Domain has no MX records — deliverability summary flags it as non-mail-receiving
- DNS-over-HTTPS resolver timeout or upstream failure — may return error or empty response
- Malformed domain input — may return validation error
- Domain exists but has partial email configuration (e.g. MX present but no SPF/DMARC) — summary reflects degraded configuration

## How this service works

Can this domain receive mail, and is it configured seriously? MX, SPF and DMARC via DNS-over-HTTPS with a deliverability summary. JSON.

## Output

A JSON object containing the results of DNS-over-HTTPS lookups for the domain's MX records (mail server presence), SPF record (sender policy), and DMARC record (authentication policy), along with an overall deliverability summary indicating whether the domain is seriously configured to receive email.

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/polyform-email-domain-deliverability-check-bac5c666/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from polyform.polyform-org.workers.dev](https://www.zero.xyz/host/polyform.polyform-org.workers.dev/llms.txt)