# MX Deliverability Verifier

> MX Deliverability Verifier is a paid API for AI agents from mcp-gateway.agentdiet.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-22).

Verifies the deliverability of an email address by checking MX records and related email routing signals

## Facts

- Endpoint: GET https://mcp-gateway.agentdiet.dev/v1/mx-deliverability-verifier?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/mx-deliverability-verifier-f7ddf0b6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1rKHvMn5h5Yxer4aT2RGe

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 mx-deliverability-verifier-f7ddf0b6
```

Example prompt: Can you check whether the email address john.doe@example.com is actually deliverable — like, does the domain have valid MX records and will an email sent there have a chance of being received?

## When to prefer this

Use this endpoint when you need to quickly validate email deliverability by checking MX records and routing infrastructure before sending messages, especially in automated workflows where bounce prevention matters and per-call cost ($0.005 USDC) is acceptable. Prefer this over purely syntactic email validators when you need to confirm the domain actually receives mail, not just that the address is formatted correctly.

## Known failure modes

- Missing or invalid email query parameter — returns an error or empty data
- Domain with no MX records — returns deliverability failure in data payload
- Payment not settled in USDC on Base — HTTP 402 returned before processing
- Malformed email address input — may return validation error or unexpected data
- Upstream DNS lookup failure — service may return partial or error result

## How this service works

Deterministic B2A/A2A/MCP/x402/MPP/L402 execution and intelligence node at https://mcp-gateway.agentdiet.dev settling in USDC on Base.

## Output

Returns a JSON object with a status field ('ok' on success), a data object containing deliverability details such as MX record presence and validity, and an roi_proof field showing compression ratio. The result indicates whether the email address has valid mail exchange infrastructure.

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {},
  "status": "ok",
  "roi_proof": {
   "compression_ratio_pct": 91.4
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/mx-deliverability-verifier-f7ddf0b6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mcp-gateway.agentdiet.dev](https://www.zero.xyz/host/mcp-gateway.agentdiet.dev/llms.txt)