SSL Certificate Checker

Connects to any TLS service and verifies the certificate and its full chain — expiry, hostname coverage, and whether the intermediates are installed correctly so every device trusts it.

Check a certificate

Common TLS ports

443	HTTPS (websites)
465	SMTPS (mail submission)
993	IMAPS (mailbox access)
995	POP3S
8443	Alt HTTPS (appliances, panels)
3389	RDP (also uses TLS)

Why intermediates matter

Your certificate isn't signed by a trusted root directly — it's signed by an intermediate, which is signed by the root that devices ship with. The server must send the site certificate plus every intermediate (the "ca-bundle"). If it doesn't, devices can't build the path to a root they trust and show certificate errors — except some browsers, which quietly download the missing piece and mask the problem. Always install the full chain your CA provides, in order: site certificate first, then intermediates.

SSL Certificate Checker

Check a certificate

Certificate chain (as served)