Check whether a mail server offers STARTTLS and modern authentication. The test runs from this server and does not send a message.
The letter comes from HSTS, Content-Security-Policy, frame protection, and X-Content-Type-Options. A certificate can be valid and the grade can still be low.
It does not complete a full SSL Labs scan. It connects once on port 443 and reads the certificate plus the response headers.
Yes — free at rookvpn.com/tls with no account required.
No. All hashing runs client-side using Web Crypto and bcryptjs. Nothing leaves your browser.
No. Hashing runs in the browser.
Bcrypt on the bcrypt page. Not SHA-256 and not MD5.
The one the publisher printed, usually SHA-256.
No.