SSL Certificate Checker
Inspect any HTTPS host's certificate. Expiry, issuer, SANs, TLS version, all the things browsers check, surfaced clearly.
What this tool actually does
Opens a TCP connection to port 443 on your domain, performs a TLS handshake, extracts the peer certificate, and verifies three things: it covers the hostname (checking CN and SANs), it hasn't expired (and isn't about to), and the TLS protocol version is acceptable.
What we don't check (yet)
Certificate chain validation against a custom trust store, OCSP stapling, HSTS headers. These are useful for security audits; for routine monitoring, "does this cert work in a modern browser" is what matters.
Why one-time checks aren't enough
A cert that's fine today might be expired in 60 days. Auto-renewal can silently fail. Continuous monitoring catches both, we re-check hourly and alert at 30 days and again at 14 days remaining, so renewal failures never become outages.