# Email Domain MX Check

> Email Domain MX Check is a paid API for AI agents from x402-canary.nicolas-x402-16f380a7.workers.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Checks whether an email address's domain has valid MX records, indicating it can receive mail

## Facts

- Endpoint: POST https://x402-canary.nicolas-x402-16f380a7.workers.dev/v1/email/domain-check
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/email-domain-mx-check-c2307260
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_d6ru7ZeMOrU_Q39t66Zw7

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-domain-mx-check-c2307260 -d '<json body>'
```

Example prompt: Can you check if the domain for user@example.com actually has MX records set up so I know it can receive email before I add it to my mailing list?

## When to prefer this

Use this endpoint when you need a lightweight, pay-per-call MX record check for an email domain without setting up your own DNS resolution infrastructure. It is ideal for pre-validating email addresses before sending, gating signups, or screening leads. Prefer this over full email verification services when you only need to confirm domain-level deliverability (MX record presence) rather than individual mailbox existence.

## Known failure modes

- Missing or malformed email field returns a validation error
- Domain with no DNS records returns has_mx: false but does not indicate outright error
- Network or DNS resolution timeouts may cause delayed or failed responses
- Completely invalid email format (no @ symbol) may cause a parsing error

## How this service works

Free need-to-tool routing plus pay-per-call npm docs and TypeScript API signatures, npm breaking-change diffs, JavaScript-rendered browser snapshots and deterministic coding-agent checks via AgentCash/x402.

## Output

Returns a JSON object with a `data` field containing `has_mx` (boolean indicating whether the domain has MX DNS records) and a `meta` field with `engine: 'email-preflight'` indicating the check method used.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "email": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {
   "has_mx": true
  },
  "meta": {
   "engine": "email-preflight"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/email-domain-mx-check-c2307260/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-canary.nicolas-x402-16f380a7.workers.dev](https://www.zero.xyz/host/x402-canary.nicolas-x402-16f380a7.workers.dev/llms.txt)