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ProbeKit MTA-STS Check
x402
ProbeKit MTA-STS Check is a paid API for AI agents from api.probekit.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-30).
Validates a domain's MTA-STS policy (RFC 8461) and TLS-RPT record (RFC 8460), including DNS record presence, HTTPS policy file retrieval, certificate validity, mode, max_age, and MX host coverage.
Price / call$0.02
Success—
StatusUnknown
How this service works
Check a domain's MTA-STS setup (RFC 8461): the _mta-sts record, the HTTPS policy file with certificate check and no redirects, mode, max_age and whether every MX host is covered, plus the TLS-RPT record (RFC 8460). Use when an agent must tell whether inbound mail is protected against TLS downgrade, or why senders report MTA-STS failures for a domain.
Output
Returns a structured report covering: presence and content of the _mta-sts TXT DNS record, the HTTPS MTA-STS policy file (fetched without redirects, with TLS certificate validation), policy mode (none/testing/enforce), max_age value, which MX hosts are and aren't covered by the policy, and the TLS-RPT DNS record (RFC 8460) including reporting endpoints.
Example use cases
Diagnosing MTA-STS delivery failures
“Senders are reporting MTA-STS validation errors when delivering mail to acmecorp.com — can you check the MTA-STS configuration and tell me exactly what's broken, including whether the policy file is reachable, the certificate is valid, and all MX hosts are listed?”
Pre-deployment MTA-STS audit
“We're about to enforce MTA-STS for mailservice.io — before we flip the mode to enforce, can you verify the _mta-sts record, policy file, TLS cert, max_age, and MX coverage are all correct?”
Checking TLS-RPT reporting readiness
“Does example.org have a TLS-RPT record set up alongside its MTA-STS policy so senders can report delivery failures?”
Technical details
Endpoint
GEThttps://api.probekit.dev/v1/mail/mta-sts?utm_source=zero.xyzWhen to prefer
Use this endpoint when you specifically need to audit or debug MTA-STS (RFC 8461) and TLS-RPT (RFC 8460) configuration for a domain — it goes deeper than a generic mail check by fetching and validating the HTTPS policy file, checking TLS certificates, verifying MX coverage, and inspecting TLS-RPT. Prefer the full mail report endpoint if you also need SPF, DMARC, and MX together in one call.
Side effects
- Domain does not exist or has no DNS — returns error or empty results
- _mta-sts record missing — flagged as not configured
- Policy file unreachable over HTTPS — connection or certificate error reported
- Policy file redirects detected — flagged as non-compliant per RFC
- MX hosts not covered by policy — listed as uncovered
- TLS-RPT record absent — flagged as missing
- Malformed policy file syntax — parse errors reported
- Invalid or expired TLS certificate on mta-sts hostname — flagged
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object |
Tags
x402
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