SSL Certificate Checker
Security & SSL
Validate SSL/TLS certificates, check expiry dates, verify certificate chains, and ensure your website's HTTPS configuration is secure.
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What is SSL/TLS?
SSL (Secure Sockets Layer) and its successor TLS (Transport Layer Security) are cryptographic protocols that provide secure communication over the internet. When you see HTTPS and the padlock icon in your browser, that means SSL/TLS is protecting the connection.
SSL certificates are digital documents that bind a website's identity to a cryptographic key pair. They enable:
- • Encryption: Data transmitted between browser and server is encrypted
- • Authentication: Verifies the website is who it claims to be
- • Data Integrity: Ensures data isn't tampered with during transmission
Why Check SSL Certificates?
Expired Certificates Break Sites
When SSL certificates expire, browsers show scary warnings that drive away ~90% of visitors. Users see "Your connection is not private" and can't access your site.
SEO Penalties
Google requires HTTPS for all websites and ranks them higher. Sites without valid SSL certificates are penalized in search results.
Trust and Credibility
Customers won't enter payment information on sites with SSL warnings. Valid HTTPS is essential for e-commerce and user trust.
Prevent Downtime
Regular SSL monitoring helps you renew certificates before they expire, preventing unexpected site outages.
How to Use the SSL Checker
Enter Your Domain
Enter your website's domain name. You can include or omit https://:
✓ example.com
✓ https://example.com
✓ www.example.com
Review Certificate Details
The tool will display comprehensive certificate information:
- ✓ Validity Status: Valid or expired
- ✓ Expiry Date: When the certificate expires
- ✓ Days Remaining: Time left before renewal needed
- ✓ Issuer: Certificate authority (Let's Encrypt, DigiCert, etc.)
- ✓ Common Name: Domain the certificate is issued for
- ✓ Subject Alternative Names: Additional covered domains
- ✓ Certificate Chain: Root and intermediate certificates
- ✓ Encryption Strength: Key size and algorithm
Check for Issues
Look for warnings about:
- 🔴 Certificate expired or expiring soon
- 🔴 Certificate doesn't match domain
- 🔴 Incomplete certificate chain
- 🟡 Weak encryption algorithms
- 🟡 Self-signed certificates
Take Action
If issues are found, renew or fix your SSL certificate before it impacts users.
Try SSL CheckerWhat We Check
Certificate Validity
Verifies the certificate is currently valid and hasn't expired. We check both the "valid from" and "valid until" dates.
Domain Name Match
Ensures the certificate's Common Name (CN) or Subject Alternative Names (SAN) match your domain. Mismatches cause browser warnings.
Certificate Chain
Validates the complete chain of trust from your certificate to the root CA. Missing intermediate certificates cause errors on some devices.
Certificate Authority Trust
Checks if the issuing CA is trusted by major browsers. Self-signed certificates trigger warnings.
Expiration Alerts
Warns you when certificates are expiring within 30 days, giving you time to renew before downtime occurs.
Encryption Strength
Analyzes key size (2048-bit minimum recommended) and signature algorithms (SHA-256 or better).
Common SSL Issues
Mixed Content Warnings
Cause: HTTPS page loading HTTP resources (images, scripts, CSS)
Solution: Update all resource URLs to use HTTPS or protocol-relative URLs (//)
Certificate Name Mismatch
Cause: Accessing www.example.com but certificate only covers example.com
Solution: Use wildcard certificate (*.example.com) or add all domains as SANs
Incomplete Certificate Chain
Cause: Missing intermediate certificates in server configuration
Solution: Install the full certificate bundle including intermediate certs
Expired Certificates
Cause: Certificate renewal forgotten or auto-renewal failed
Solution: Set up automated renewal (certbot for Let's Encrypt) and monitoring alerts
Self-Signed Certificates
Cause: Using certificates not issued by trusted CA
Solution: Use free Let's Encrypt certificates or purchase from trusted CA
Best Practices
Enable Auto-Renewal
Use Let's Encrypt with certbot's automatic renewal, or enable auto-renewal with your certificate provider. Test renewal process quarterly.
Monitor Expiration Dates
Set up monitoring alerts 30, 14, and 7 days before expiration. Check all subdomains, not just the main domain.
Use Strong Encryption
Use 2048-bit or 4096-bit RSA keys (or 256-bit ECC). Disable older TLS versions (TLS 1.0, 1.1) and use TLS 1.2+ only.
Cover All Domains
Use wildcard certificates (*.example.com) or multi-domain (SAN) certificates to cover www, API, CDN, and other subdomains.
Implement HSTS
Enable HTTP Strict Transport Security (HSTS) header to force browsers to always use HTTPS, preventing downgrade attacks.
Regular Audits
Run monthly SSL checks using our tool and services like SSL Labs to catch configuration issues early.