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TLS Certificate Checker

Check certificate expiry, issuer, and security configuration

Quick connectivity check

Full certificate analysis (paste openssl output)

Run openssl s_client -connect your-site.com:443 -servername your-site.com 2>/dev/null | openssl x509 -noout -subject -issuer -dates -ext subjectAltName and paste the output above.

About the Tls Checker

TLS certificates are the foundation of encryption in transit — SOC 2 control CC6.1 requires that all data transmitted over public networks is encrypted. Expired certificates cause outages, browser warnings, and audit findings. Regular certificate monitoring is a basic operational security requirement.

This checker parses OpenSSL certificate output to show expiry dates, issuer, subject alternative names, and remaining validity. The quick connectivity test verifies that HTTPS is working; the paste mode gives you full certificate details for audit documentation. All analysis is local — certificate data never leaves your browser.

How to use

  1. For a quick check: enter a URL and click Check.
  2. For full analysis: run openssl s_client and paste the output.
  3. Review the expiry status (green, amber, red).
  4. Document the findings for your SOC 2 audit evidence.

Frequently Asked Questions

How often should I check my TLS certificates? ▾

SOC 2 requires continuous monitoring of security controls. In practice: automated daily checks with alerting at 30/14/7/1 days before expiry. Use this tool for manual spot checks and audit documentation.

What TLS version should we support? ▾

TLS 1.2 minimum (TLS 1.3 preferred). TLS 1.0 and 1.1 are deprecated and will fail SOC 2 review. Check with openssl s_client -tls1_1 to verify older versions are rejected.

Why can browsers not read certificate details? ▾

JavaScript cannot access certificate information for security reasons. Use the openssl command shown above in a terminal for full certificate analysis, then paste the output here.

Is this tool free to use? ▾

Yes! This tool is 100% free. No signup, no credit card, no limits. It's part of Formatho's privacy-first developer toolkit.

Is my data safe? Does this tool send data to a server? ▾

Absolutely. This tool runs entirely in your browser. Your data never leaves your device. Zero server-side processing, zero tracking.