Independent tools worth bookmarking — checking a certificate, decoding a CSR, or finding exactly which resource is breaking your padlock. All free, no account required.
The industry-standard deep scan of your server's certificate, protocol support, and configuration, with a letter grade.
Qualys SSL Labs →Quick check of a certificate's validity, expiry date, and chain — good for a fast sanity check.
SSL Shopper →Paste a CSR to verify its domain, organization, and key details before submitting it to a CA.
SSL Shopper →Paste a certificate to read its exact fields — issuer, validity window, and Subject Alternative Names.
SSL Shopper →Scans a page for the specific mixed-content resources breaking the padlock, with the exact offending URLs.
WhyNoPadlock.com →Search public Certificate Transparency logs for every certificate ever issued for a domain — useful for auditing.
Certificate Transparency →