Expiry date, issuer, hostnames covered, chain, and TLS version, in seconds. Free, no account needed.
Exact expiry date, days remaining, and whether the certificate is valid right now.
Who issued the certificate and the full chain from leaf to root.
Every domain the certificate is valid for, from its Subject Alternative Names.
The negotiated TLS version and the certificate's key type and size.
Whether the plain http:// address redirects visitors to https://.
Whether the site sends a Strict-Transport-Security header.
It opens a live TLS connection to the domain on port 443 and reports whether the certificate is valid, when it expires, who issued it, which hostnames it covers, and the full certificate chain.
Enter the domain and run the check. The report shows the exact expiry date and how many days are left, read straight from the certificate the server presents.
A certificate reads as untrusted when it's self-signed, the chain sent by the server is incomplete, or it doesn't cover the hostname you checked. The report tells you which of these applies.
HTTP→HTTPS shows whether the plain http:// address redirects to https://. HSTS shows whether the site sends a Strict-Transport-Security header telling browsers to always use HTTPS. Both help search engines and users reach the secure version.
Checks are free and unlimited. To be warned automatically before a certificate lapses, monitor the domain with a free account and get an alert as expiry approaches.
Uptimeprobe watches your certificates and your uptime, and alerts you before anything lapses.
Start monitoring free