How to check an SSL certificate

The short answer

Check that the certificate is valid for the hostname, issued by a trusted authority, and not close to expiration.

Step by step

1. Enter the public HTTPS hostname.
2. Run SSL Checker.
3. Review issuer, subject, SAN entries, and remaining validity.
4. Test the final HTTPS URL separately if redirects are involved.

Technical details

• The hostname must appear in the certificate's subject alternative names. Certificate validity does not by itself prove that every TLS setting is ideal.

Common mistakes

• Checking the wrong hostname behind a redirect.
• Confusing certificate expiry with domain registration expiry.
• Ignoring intermediate certificate or client compatibility issues.

Limitations

• Browser-safe certificate checks expose a focused view and do not replace a full TLS configuration assessment.