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SiteCheck Web Intel MTA-STS Validator
x402
SiteCheck Web Intel MTA-STS Validator is a paid API for AI agents from api.webintel-api.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-24).
Validates a mail domain's MTA-STS configuration by checking the _mta-sts TXT DNS record and the HTTPS policy file, reporting their presence, mode, MX patterns, and max_age.
Price / call$0.002
Success—
StatusUnknown
How this service works
Checks MTA-STS for a mail domain: the _mta-sts TXT record (v=STSv1 and id) and the HTTPS policy file (mode enforce, testing or none, the MX patterns and max_age). Reports whether the record and the policy are both present and whether the policy's version is valid. Does not test the mail servers themselves.
Output
Returns whether the _mta-sts TXT DNS record exists with v=STSv1 and an id, whether the HTTPS policy file at /.well-known/mta-sts.txt is reachable and syntactically valid, the policy mode (enforce, testing, or none), the list of MX host patterns allowed, the max_age value, and an overall summary of whether both the record and policy are present and valid.
Example use cases
Email security audit for new domain
“We just set up MTA-STS for our company domain acme.com — can you verify the _mta-sts TXT record is in place, confirm the policy file is reachable over HTTPS, and tell me if the mode is set to enforce?”
Diagnose MTA-STS misconfiguration
“Emails to our domain techstartup.io are bouncing from strict senders — can you check our MTA-STS setup and tell me if the DNS record and policy file are both valid and what mode they're showing?”
Monitor third-party mail domain posture
“I need to verify whether our vendor's mail domain supplierco.net has MTA-STS properly configured before we start exchanging sensitive emails — check the policy mode, MX patterns, and max_age for me.”
Technical details
Endpoint
GEThttps://api.webintel-api.workers.dev/api/security/mta-sts-validator?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a quick, automated check of a mail domain's MTA-STS posture without standing up your own DNS resolver or HTTP client logic. It is ideal for email security audits, onboarding checks, compliance monitoring, and troubleshooting MTA-STS deployment issues. It does not test the actual mail servers, so pair it with SMTP-level checks if full delivery path validation is needed.
Side effects
- Domain does not exist or has no DNS records — returns absence flags
- _mta-sts TXT record missing — returns record not found
- HTTPS policy file unreachable or returns non-200 — reports policy fetch failure
- Policy file present but malformed or missing required fields — reports invalid policy
- Network timeout fetching the policy file — may return error or partial result
- Domain parameter missing from query — likely returns 400 or validation error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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