Certificate Transparency Monitor

Monitor CT logs for certificates issued for your domain

About CT Monitoring

Certificate Transparency (CT) monitoring provides continuous visibility into all TLS certificates issued for your domains. By regularly querying CT logs, you can detect unauthorized certificate issuances, track certificate renewals, and maintain an accurate inventory of your TLS certificate landscape. Our CT Monitor helps security teams stay on top of certificate activity and quickly identify potential security incidents.

How to Use

Enter the domain name you want to monitor (e.g., example.com).
Click Search to query Certificate Transparency logs for recent certificates.
Review the list of discovered certificates including issuer and validity details.
Investigate any unexpected or unauthorized certificates immediately.

Use Cases

Rogue Certificate Detection: Identify certificates issued without your authorization, indicating potential security breaches.
Certificate Inventory: Maintain a comprehensive list of all certificates associated with your organization's domains.
Expiry Monitoring: Track certificate renewal patterns and ensure timely reissuance before expiration.
Compliance Verification: Confirm that all certificates for your domains are properly logged in CT logs.

Frequently Asked Questions

For production environments, CT logs should be monitored daily or even in real-time. The sooner you detect an unauthorized certificate, the faster you can respond by revoking it and investigating the breach.

If you find an unexpected certificate, first verify if it was legitimately issued (e.g., by another team). If it's unauthorized, contact the issuing CA immediately to request revocation, and investigate how the certificate was issued without your approval.

Yes, you can use this tool to check any domain. For enterprise-scale monitoring across many domains, consider our Batch Certificate Checker tool or programmatic access to the CT log APIs for automated monitoring workflows.

Tips & Best Practices

•Monitor all domains including those without active certificates
•Set up both email and webhook alerts for maximum visibility
•Combine CT monitoring with DNS monitoring for comprehensive security
•Review alert history regularly to identify patterns or recurring issues

Technical Details

Logs: All public CT logs including Google, Cloudflare, DigiCert
Speed: Near real-time detection (typically within 5-15 minutes)
Alerts: Email, webhook, and Slack notifications
History: Complete audit trail of all detected certificates