#email-security

Inspect a domain's SMTP transport-security posture — whether mail servers are required to deliver inbound mail over authenticated TLS, protecting it from downgrade and man-in-the-middle attacks. Pass a domain and the service fetches the MTA-STS policy file from mta-sts.<domain>/.well-known/mta-sts.txt (its version, mode, the permitted MX hosts and max_age), the _mta-sts DNS TXT record (its policy id) and the _smtp._tls TLS-RPT record (the rua reporting address), then reports whether MTA-STS is actually enforced and a prioritised list of issues — no policy file, no DNS record, a mode of only "testing", or a missing TLS-RPT record. A second endpoint returns just the parsed policy file. The request is made server-side and private/internal targets are refused (SSRF-guarded). Built for email-deliverability and anti-downgrade-attack audits, vendor and third-party assessment, and compliance. An MTA-STS / TLS-RPT checker — the SMTP transport-security counterpart to the email-authentication analyzer (emailsec, which covers SPF, DKIM and DMARC), and distinct from raw DNS lookup (dns). No upstream key, no cache.

api.oanor.com/mtasts-api

Inspect any domain's email-authentication posture — its protection against spoofing and phishing — via live DNS. Pass a domain and the service looks up and validates SPF (the v=spf1 record, its all-qualifier and the 10-lookup limit), DMARC (the _dmarc policy p=none/quarantine/reject, plus sp, pct and rua/ruf reporting addresses), DKIM (probing the common selectors at selector._domainkey, or pass your own), BIMI and the MX servers — then returns an A+-to-F grade with a prioritised list of issues and concrete advice. A second endpoint parses the DMARC record tag by tag with a plain-English interpretation of the policy. Built for email-deliverability and anti-spoofing audits, vendor and third-party risk assessment, security onboarding and continuous monitoring. An email-authentication analyzer — distinct from mailbox/address validation (email), raw DNS record lookup (dns) and the HTTP security-header grader (secheaders). Pure live DNS, no upstream key, no cache.

api.oanor.com/emailsec-api