SSL Tools
SSL Certificate Checker
Instantly check a domain's SSL certificate status, expiry date, issuer, and full certificate details.
Enter any domain below to instantly check its SSL certificate - validity, expiry date, issuer, certificate authority, TLS version, and more.
JustChecker monitors your SSL certificates automatically and alerts you before they expire - never lose customer trust to a browser warning again.
Frequently Asked Questions
It connects to your domain on port 443, retrieves the live certificate the server is presenting, and reports its issuer, subject, validity dates, and whether the chain of trust back to a recognized root certificate authority is intact.
Browsers cache trust decisions and may already have loaded a page before a certificate expired or changed. A fresh server-side check reflects the certificate exactly as it is right now, catching problems your browser tab hasn't noticed yet.
Your server's certificate is normally signed by an intermediate certificate, which is itself signed by a trusted root. If the server fails to send the intermediate, browsers show a trust error even though your certificate itself is valid - this checker verifies the full chain, not just the leaf certificate.
Yes - the certificate's Subject Alternative Names (SAN) list is read directly from the certificate, so if it was issued for *.yourdomain.com, every subdomain it actually covers is shown.
This checker connects on the standard HTTPS port (443), covering the overwhelming majority of production websites - the certificate itself is unaffected by this tool's scope and would report identically wherever it's served.
A self-signed certificate has the same entity as both issuer and subject, rather than a trusted certificate authority. Browsers show a security warning for these unless manually trusted - common for internal/development environments, not appropriate for a public production site.
Yes - the certificate's signature algorithm (e.g. SHA-256 vs. the deprecated SHA-1) is read directly from the certificate data and reported, since SHA-1-signed certificates are no longer trusted by modern browsers.
This tool examines the certificate itself (issuer, validity, chain). The TLS Version Checker instead tests which TLS protocol versions your server is willing to negotiate a connection with - related but distinct aspects of your HTTPS setup.