MX record lookup for any domain, paid via x402 protocol
What it does
The Mailcheck API MX endpoint (`/mailcheck/mx`) performs DNS MX record lookups for a given domain. It is part of a broader Mailcheck API hosted at mailcheck.hugen.tokyo that offers six email validation checks: syntax validation, MX record lookup, disposable domain detection (5,000+ domains), free provider detection, role-based address detection, and typo suggestions.
The `/mailcheck/mx` endpoint specifically accepts a `domain` query parameter (max 253 characters) via GET and returns a JSON response indicating whether MX records were found and listing them. The broader API also exposes `/mailcheck/validate` (POST, full validation suite) and `/mailcheck/disposable` (GET, disposable domain check). The API is documented via OpenAPI 3.1 with full response schemas.
Note: Although this endpoint is listed as an x402-paid endpoint, the probe did not successfully capture a 402 payment challenge — the endpoint returned 405 on POST and 410 (Gone) on GET. This may indicate the endpoint is temporarily unavailable, has been removed, or the x402 payment gate is misconfigured. No pricing information could be determined. The root URL returns 404, and no dedicated pricing or README pages exist. Treat this listing with caution until liveness can be confirmed.
Capabilities
Use cases
- —Verifying that a domain has valid mail exchange records before sending email
- —Pre-screening email addresses by checking if their domain accepts mail
- —Building email validation pipelines that need MX record data
- —Detecting domains that cannot receive email due to missing MX configuration
Fit
Best for
- —Agents needing quick MX record lookups without managing DNS libraries
- —Email validation workflows requiring domain-level mail server checks
- —Automated systems that verify deliverability before sending messages
Not for
- —Full SMTP-level email deliverability verification (no mailbox probing)
- —Bulk email list cleaning at high volume (no rate limit or batch info available)
- —Use cases requiring guaranteed uptime — endpoint liveness is currently uncertain
Quick start
curl "https://mailcheck.hugen.tokyo/mailcheck/mx?domain=gmail.com"Example
Response
{
"domain": "gmail.com",
"mx_found": true,
"mx_records": [
"gmail-smtp-in.l.google.com",
"alt1.gmail-smtp-in.l.google.com",
"alt2.gmail-smtp-in.l.google.com"
]
}Endpoint
Quality
The OpenAPI schema is well-defined with clear request/response models, but the endpoint did not return a 402 challenge on any method (405 on POST, 410 on GET), suggesting it may be down or removed. No pricing information is available. Root and ancillary pages all return 404.
Warnings
- —Endpoint returned 405 (POST) and 410 Gone (GET) — x402 payment challenge was NOT captured; endpoint may be offline or decommissioned
- —No pricing or payment details could be determined from the probe
- —Root URL returns 404; no landing page, pricing page, or README exists
- —The 410 Gone status on GET is particularly concerning and may indicate the resource has been permanently removed
Citations
- —The Mailcheck API provides 6 email validation checks: syntax, MX records, disposable detection (5,000+ domains), free provider, role-based, and typo suggestionhttps://mailcheck.hugen.tokyo/docs
- —The /mailcheck/mx endpoint accepts a domain query parameter (max 253 chars) and returns domain, mx_found, and mx_records fieldshttps://mailcheck.hugen.tokyo/docs
- —Endpoint returned 405 on POST and 410 on GET during probehttps://mailcheck.hugen.tokyo/mx