# B2A Email Deliverability, MX, SPF & DMARC Verifier

> B2A Email Deliverability, MX, SPF & DMARC Verifier is a paid API for AI agents from prompt-guard.agentdiet.dev, paid per call via MPP, $0.005/call, status unknown (last checked 2026-10-23).

Validates an email address for syntax correctness, disposable/burner provider status, role account detection, and live DNS MX/SPF/DMARC record checks to assess deliverability.

## Facts

- Endpoint: POST https://prompt-guard.agentdiet.dev/v1/mx-deliverability-verifier?utm_source=zero.xyz
- Price: $0.005/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Provider: prompt-guard.agentdiet.dev
- Website: https://prompt-guard.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/prompt-guard-agentdiet-dev-b2a-email-deliverability-mx-spf-dmarc-919409f1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_IGAMwJE8gFsc_wC4Zfnju

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 prompt-guard-agentdiet-dev-b2a-email-deliverability-mx-spf-dmarc-919409f1 -d '<json body>'
```

Example prompt: Can you check whether john.doe@acmecorp.com is a real, deliverable email — specifically whether it passes syntax checks, isn't a disposable/burner address, and has valid MX, SPF, and DMARC records set up on the domain?

## When to prefer this

Choose this endpoint when you need a comprehensive, multi-signal email validation that goes beyond simple syntax checking — specifically when you need live DNS MX/SPF/DMARC lookups combined with disposable provider detection and role account flagging in a single call. It is especially suited for B2B lead enrichment pipelines, user signup screening, or pre-send deliverability audits where a lightweight regex check is insufficient.

## Known failure modes

- Invalid or malformed email input returns a syntax error
- Domain does not exist or has no DNS records, resulting in MX lookup failure
- Transient DNS resolution timeouts for live record checks
- Disposable provider database may not cover all emerging throwaway services
- Payment failure via x402 if USDC balance is insufficient

## How this service works

Validates email syntax, disposable/burner provider status, role accounts, and live DNS MX/SPF/DMARC records. (Live x402 v2, IETF MPP & MCP endpoint at https://prompt-guard.agentdiet.dev/v1/mx-deliverability-verifier)

## Output

Returns a structured object indicating email syntax validity, whether the domain is a known disposable/burner provider, whether the address is a role account (e.g. admin@, info@), and live DNS lookup results for MX records (mail servers), SPF policy, and DMARC policy — giving a comprehensive picture of whether the email is safe and likely deliverable.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "email"
 ],
 "properties": {
  "email": {
   "type": "string",
   "minLength": 1,
   "description": "Email address to validate for syntax, MX deliverability, and disposable risk"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/prompt-guard-agentdiet-dev-b2a-email-deliverability-mx-spf-dmarc-919409f1/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from prompt-guard.agentdiet.dev](https://www.zero.xyz/host/prompt-guard.agentdiet.dev/llms.txt)