Deliverability Score

What gets checked

MX — records exist, hostnames resolve, null-MX detected
SPF — syntax, -all vs ~all vs +all, duplicate records, and the 10-DNS-lookup limit counted recursively through includes
DKIM — public keys probed across 15 common selectors
DMARC — policy strength (reject / quarantine / none), pct coverage, rua reporting
MTA-STS + TLS-RPT — enforced TLS policy and failure reporting
Reverse DNS — forward-confirmed PTR on every mail server
Domain age — via RDAP; new domains face spam-filter suspicion
BIMI — bonus points for brand indicators

Only public DNS records are read — no mail is sent, nothing is stored. DKIM absence is reported as "not detected", never as proof.