Free tool
SSL Certificate Checker
Enter a domain to see its certificate's expiry date, issuer, SANs, and whether it's trusted by standard certificate authorities.
Questions
Does this check the full certificate chain?
It validates against Node.js's built-in trusted CA store (the same one most server-side HTTP clients use) and reports whether the chain is trusted, plus the specific error if not — expired, self-signed, hostname mismatch, and so on.
Can I check an internal or private domain?
No — this runs server-side, so checks against localhost or private/internal IP ranges are blocked to avoid using the tool to probe internal networks.
What port does this check?
Port 443 by default. Paste a full URL with a different port (e.g. https://example.com:8443) to check that instead.
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