SSL certificate lookup explained
Check TLS certificates for any domain or IP and read issuer, validity, chain trust, and negotiated TLS security.
When to use it
Use an SSL certificate check when a site shows browser trust warnings, before a certificate renewal deadline, after a migration to a new host or CDN, or when verifying that HTTPS is configured on the expected port.
What to inspect
Start with the issuer and validity window, then confirm the subject alternative names cover the hostname you queried. The chain view shows intermediate certificates, and the handshake details reveal the negotiated TLS version, cipher suite, and ALPN protocol.
How to read trust failures
A certificate can be unexpired but still untrusted when the chain is incomplete, the hostname does not match the SAN list, or the issuer is not in the system root pool. The verification error message points to the exact reason.