Free SSL/TLS Certificate Tools
Diagnose certificate issues, verify your TLS chain, decode PEM data, and generate CAA records — no account required.
SSL Certificate Chain Checker
Verify your server's TLS certificate chain is complete and correctly configured. Checks for expired certificates, missing intermediates, hostname mismatches, and OCSP status.
Check your chain →SSL Certificate Expiry Checker
Check when any SSL/TLS certificate expires. Shows exact expiry date, remaining days, and issuer for any public website.
Check expiry →X.509 Certificate Decoder
Paste a PEM-encoded certificate and see every field: subject, issuer, validity, SANs, key algorithm, and SHA-256 fingerprint. Runs entirely in your browser.
Decode a certificate →CSR Decoder
Decode a PKCS#10 Certificate Signing Request. View subject, key algorithm, key size, and requested SANs. Nothing is uploaded.
Decode a CSR →CAA Record Checker & Generator
Look up existing CAA DNS records for any domain and generate new ones. Control which Certificate Authorities can issue certificates for your domain.
Check CAA records →Why Use These Tools?
SSL/TLS misconfigurations are one of the most common causes of website downtime and security warnings. An incomplete certificate chain, an expired intermediate, or missing CAA records can cause browsers to reject your site — even when your leaf certificate is perfectly valid. These free tools help you catch issues before your visitors do.
Need ongoing certificate monitoring?
CertShield monitors your certificates 24/7 and alerts you before they expire or change unexpectedly.
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