mailsec.protonmail.ch handles mail for 856 domain(s) we track — ordinary email domains.
This is one of several mail servers run by the same operator. mail.protonmail.ch handles 882 domain(s) and has the fuller list.
Showing 200 of 856 recorded domains.
See whether a specific domain is disposable, forwarding or safe — and which mail server it actually uses.
Enter a domain to look up its mail server and trust signals
Checking syntax, MX, SMTP, trust, gateway, and domain profile…
Enter a domain above and click Check to see results.
A mail server's reputation is one signal. The API scores every signup against the whole catalogue — disposable pools, low-trust domains, catch-alls and gateways — as it grows.
What you unlock