SSL Certificate Checker: Inspect TLS Security

We perform a real TLS handshake to the target domain and extract: certificate subject and issuer, Subject Alternative Names (SANs), validity dates, TLS protocol version, cipher suite, and whether the full certificate chain validates against trusted CAs.

At minimum, set up automated monitoring to alert 30 and 7 days before expiry. Let's Encrypt certificates expire every 90 days — if auto-renewal breaks silently, you'll find out from your customers. DevHelm's continuous monitoring catches cert issues within 30 seconds.

A valid chain means every certificate in the chain (leaf → intermediate → root) is correctly signed by its parent, none are expired, and the root CA is in the system trust store. An invalid chain triggers browser warnings even if the leaf cert itself is fine.

TLS 1.3 is the current standard — faster handshakes, better security. TLS 1.2 is acceptable. TLS 1.0 and 1.1 are deprecated and should be disabled. Major browsers have dropped support for anything below TLS 1.2.