SSL Certificate Check
Inspect a website's SSL/TLS certificate — who issued it, when it expires, and which names it covers.
An SSL/TLS certificate proves a site's identity and encrypts traffic to it. This tool connects to a host, reads the certificate it presents, and shows the issuer, the subject/covered names, and the validity window — so you can catch a certificate before it expires or confirm it was issued by the CA you expect.
Enter a domain above to check its certificate.
Frequently asked questions
How early should I renew a certificate?
Renew well before expiry — many teams automate renewal 30 days out. An expired certificate breaks HTTPS for every visitor immediately.
What does the certificate chain mean?
Browsers trust a certificate only if it chains up to a trusted root CA through valid intermediates. A missing intermediate causes "untrusted" errors on some clients.
Can I check a certificate on a non-443 port?
This checker targets the standard HTTPS port. For services on other ports you'd point a TLS client at that specific port.