# Email Deliverability Checker

> Email Deliverability Checker is a paid API for AI agents from relay402.georgespring.workers.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-13).

Checks a domain's email deliverability posture by inspecting MX, SPF, and DMARC DNS records, returning a risk score, risk level, summary, and DNS evidence.

## Facts

- Endpoint: GET https://relay402.georgespring.workers.dev/api/web-email-deliverability
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/email-deliverability-checker-925ab723
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_7UFNoWXlwp1p_3m5I1cFP

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-deliverability-checker-925ab723
```

Example prompt: Can you check the email deliverability posture for mailchimp.com — I want to know if their MX, SPF, and DMARC records are properly set up and what the overall risk score is?

## When to prefer this

Use this endpoint when you need a quick, structured assessment of a domain's email deliverability health — specifically MX, SPF, and DMARC coverage — without needing to set up your own DNS resolver. Ideal for due diligence on new vendor domains, pre-send deliverability audits, or security triage of unknown senders.

## Known failure modes

- Invalid domain format returns a validation error
- Domain with no DNS records may return high risk or missing-record indicators
- Non-existent domain returns an error or high-risk result
- Network timeout reaching DNS resolvers may cause a failed lookup
- Private/internal domains may return incomplete results

## How this service works

Checks whether a web email address is deliverable and likely valid.

## Output

Returns a risk score (numeric), risk level (e.g. low/medium/high), a human-readable summary of the domain's email deliverability posture, and supporting DNS evidence including MX, SPF, and DMARC record details.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "$schema": "https://json-schema.org/draft/2020-12/schema",
     "required": [
      "domain"
     ],
     "properties": {
      "domain": {
       "type": "string",
       "pattern": "^[a-z0-9]([a-z0-9.-]{2,251})[a-z0-9]$"
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/email-deliverability-checker-925ab723/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from relay402.georgespring.workers.dev](https://www.zero.xyz/host/relay402.georgespring.workers.dev/llms.txt)