Client-Side UtilityLocal memory execution • Zero server telemetry
SSL Certificate Checker & Expiration Monitor
Inspect live SSL/TLS certificates, verify chain of trust, monitor days until expiration, review Subject Alternative Names (SANs), and check TLS protocol versions.
SMaintained by Security & Infrastructure Desk
Published
SSL Certificate Target
Quick examples:
Ready to verify SSL certificate
Enter any domain above to check SSL certificate status, chain validity, expiry dates, and encryption standards.
SMaintained by Security & Infrastructure Desk
Published
Calculation Methodology & Formula
Initiates a secure TLS socket connection to port 443 to inspect the peer X.509 certificate and verify cryptographic validity, expiration timelines, and cipher suites.
TLS Handshake: Host:443 -> Peer Certificate [Issuer, SAN, ValidTo, DaysRemaining]Worked Example: Check GitHub.com Certificate Health
Verify HTTPS validity and expiration date for github.com.
hostname:github.com
port:443
Expected OutputStatus: Valid & Trusted, Issuer: DigiCert Global Root G2, Protocol: TLSv1.3
Returns real-time X.509 certificate properties and exact days until renewal.
Technical Constraints & Limitations
- Private IP networks and internal hosts (.local, .internal) are restricted by SSRF protection.
- Only inspects public endpoints accepting TLS/SSL connections.
Frequently Asked Questions
Why is SSL certificate monitoring essential?
Expired SSL certificates trigger severe browser security warnings that block visitor access completely, destroy SEO rankings, and break APIs and automated web services.
What is a Subject Alternative Name (SAN)?
A SAN allows an SSL certificate to secure multiple domain names and subdomains under a single certificate (e.g., example.com and *.example.com).
What is the recommended renewal window for SSL certificates?
Most security authorities (including Let’s Encrypt and DigiCert) recommend renewing certificates at least 30 days prior to their expiration date.