Check a TLS certificate

Live handshake from SSLert — no account required.

Paste a public hostname. We connect to port 443 (or 8443), read the certificate on the wire, and optionally look up domain registration expiry. This is the same check the hosted monitor runs.

Hostname Check certificate

We reject IP addresses and hosts that resolve to private networks. Rate limit: 20 checks per minute per IP. Want the 200 / 100 / 47-day math? Use the lifetime calculator.