SYSBOXCert Checker
Check the certificate a service actually presents
Enter a host name and pick a service above, or open /cert-checker/mail.example.com?port=443 directly.
Connects live to the host and port you choose and reports whatever certificate is actually presented - not a stored/cached result. The rating is a simple heuristic (expiry, host name match, server-auth usage, key size, signature algorithm, TLS version), not a full audit.