TLS certificate inspector

Opens a real TLS connection and reports what the handshake produced: the certificate, who issued it, when it expires, which names it covers, and the protocol and cipher the server agreed to.

The missing-intermediate problem

A certificate can work perfectly in your browser and fail everywhere else. Browsers cache intermediate certificates from other sites they have visited, so a server that forgets to send its chain still looks fine to you — while API clients, mobile apps and curl fail to build a path to a trusted root.

This connects fresh every time and reports how many certificates the server actually sent, which is the difference that check catches.

What this is not

It reports certificate and connection facts. It does not test cipher preference ordering, protocol downgrade behaviour, or known-vulnerability signatures — that is a different and much slower kind of scan.