# mailcheck-dx MX DNS Validator

> mailcheck-dx MX DNS Validator is a paid API for AI agents from mailcheck-dx.hugen.tokyo, paid per call via x402, $0.005/call, status down (last checked 2026-09-15).

Performs MX DNS lookups and validates domain mail server configuration, including basic SMTP reachability and MX record checks.

## Facts

- Endpoint: POST https://mailcheck-dx.hugen.tokyo/mx
- Price: $0.005/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/mailcheck-dx-hugen-tokyo-70c372ad
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_LD35KvwSIuUgr9QcZSAvh

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 mailcheck-dx-hugen-tokyo-70c372ad -d '<json body>'
```

Example prompt: Can you check whether the domain gmail.com has valid MX records and a reachable mail server — I want to confirm it can actually receive email before I send to addresses there.

## When to prefer this

Use this endpoint when you need to verify that a domain's mail infrastructure is properly set up at the DNS level before sending email, or when validating email addresses where domain-level deliverability (MX records + SMTP reachability) is the primary concern rather than full address-level validation.

## Known failure modes

- Domain does not exist or has no MX records — returns empty or error result
- DNS lookup timeout if the domain's nameservers are unresponsive
- SMTP reachability check blocked by firewall or rate-limiting on the mail server
- Invalid domain format in request body — returns validation error
- Payment failure via x402 protocol — request rejected before processing

## How this service works

Performs MX DNS lookups and validates domain mail server configuration, including basic SMTP reachability and MX record checks.

## Output

Returns MX record details for the queried domain along with SMTP reachability status, indicating whether the domain's mail server infrastructure is properly configured and capable of receiving email.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/mailcheck-dx-hugen-tokyo-70c372ad/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mailcheck-dx.hugen.tokyo](https://www.zero.xyz/host/mailcheck-dx.hugen.tokyo/llms.txt)