SSL Certificate Checker
Verify SSL/TLS certificate validity, expiration dates, issuer authority, and Subject Alternative Names (SAN) to avoid browser warnings and unexpected downtime.
How to Use This Tool
Run an automated assessment in three straightforward steps.
Submit Domain Name
Enter your website address (e.g. mycompany.com). You do not need to install local agents or modify firewall rules.
Direct TLS Handshake
SiteSecura establishes an outbound TLS connection on port 443, retrieving and parsing the x509 server certificate.
Inspect Expiration & Chain
Review expiration alerts, issuer details, SAN coverage, and step-by-step renewal instructions.
SSL/TLS Inspection Points
SiteSecura performs cryptographic handshakes against your domain's public IP to verify transport security.
Certificate Validity & Expiration
Uptime & TrustValidates the certificate's active date range, calculating the exact number of days remaining before expiration to prevent unexpected site outages.
Hostname & SAN Matching
Browser Warning PreventionEnsures the certificate's Subject Alternative Names (SAN) list correctly covers your apex domain and subdomains (e.g. www vs apex).
Certificate Authority (CA) Issuer
Trust Chain VerificationIdentifies the root and intermediate Certificate Authority that signed the certificate (e.g. Let's Encrypt, DigiCert, Sectigo, Cloudflare).
TLS Protocol Version Support
Cryptographic StrengthVerifies that modern transport protocols (TLS 1.2 and TLS 1.3) are supported and negotiated during connection handshakes.
Interpreting Scan Results
Every scan item receives an explicit status indicator to help you prioritize remediation.
Certificate is active, signed by a recognized public CA, matches the domain hostname, and has more than 30 days until expiry.
Certificate expires within 30 days, or supports deprecated legacy fallback protocols that should be retired.
Certificate has expired, does not match the hostname, or is self-signed, causing severe browser interstitial warnings.
Subject Alternative Names (SAN), issuer identity, and cryptographic cipher negotiated during connection.
Practical Remediation Guidance
How to resolve common gaps and harden your server configurations.
An expired or misconfigured SSL certificate immediately breaks visitor trust and triggers alarming browser interstitial errors (“Your connection is not private”). Follow these steps to resolve common SSL/TLS issues:
Automate Renewals with ACME / Certbot
Eliminate human error by enabling automatic renewals. If using Nginx or Apache on Linux, configure certbot renew as a scheduled systemd timer or cron job.
Verify Subject Alternative Names (SAN)
Always request certificates covering both example.com and www.example.com, or obtain a wildcard certificate (*.example.com) for multiple subdomains.
Serve the Full Certificate Chain
Configure your web server to present the full intermediate bundle (fullchain.pem) rather than just the leaf certificate to avoid trust errors on mobile devices.
Leverage Cloud Managed Certificates
If hosting behind Cloudflare, AWS CloudFront, or Vercel, utilize managed edge certificates which handle provisioning, renewal, and OCSP stapling automatically.
Assessment Limitations & Technical Scope
SiteSecura performs deterministic, non-intrusive perimeter checks. Understanding what a passive assessment cannot evaluate ensures responsible risk management:
- •Does not evaluate client-side mutual TLS (mTLS) certificates or private internal corporate CAs.
- •Does not grade or benchmark private cipher-suite lists beyond verifying standard TLS handshake negotiation.
- •Cannot detect revoked certificates if the issuing CA's OCSP responder or CRL server is temporarily unreachable.
- •A valid SSL certificate encrypts in-transit data but does not prevent malicious content, phishing forms, or server vulnerabilities.
- •Does not inspect hardware security module (HSM) key storage or private key entropy.
Recommended Technical Guides
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Frequently Asked Questions
Ready for a Complete Website Security Evaluation?
Run an end-to-end passive scan across HTTPS, SSL certificates, defensive HTTP response headers, and DNS email authentication records in under 60 seconds.