SSL Certificate Checkerfor Developers
Instantly validate your site's certificate: expiration, issuer trust, chain order, SAN/hostname, OCSP stapling, TLS/ALPN, HSTS and security headers.
What This SSL Checker Does
The SSL Certificate Checker inspects your site's X.509 certificate and presents an actionable report for engineers and SEOs. It validates expiration, issuer trust, chain order and completeness, Subject Alternative Names (SAN) and hostname match, supported TLS versions, and security headers.
🔍 How It Works
✅ What We Check
- • Validity & expiry (UTC timestamps, days to expiry)
- • Chain order and missing intermediates
- • Hostname & SAN matching (wildcards, IDN)
- • Certificate issuer and trust path
- • Serial number and fingerprint
- • Common misconfigurations
Why SSL Matters for SEO & Security
Security & Trust
Valid certificates protect user data and build trust. Expired or misconfigured certificates cause browser warnings and security issues.
SEO Impact
Search engines favor HTTPS sites. Certificate errors can harm crawlability, Core Web Vitals, and search rankings.
Performance
Proper certificate configuration improves connection speed and reduces handshake overhead for better user experience.
Troubleshooting Common SSL Issues
🚨 Certificate Expired
Issue: The certificate has passed its expiration date.
Solution: Renew the certificate immediately and set up monitoring with auto-renewal to prevent future expiration.
⚠️ Hostname Mismatch
Issue: The certificate's Subject Alternative Names (SAN) don't include your hostname.
Solution: Issue a new certificate with the correct SAN entries or ensure wildcard certificates cover your subdomain pattern.
🔗 Untrusted Issuer
Issue: Missing intermediate certificates or incorrect chain order.
Solution: Install the complete certificate chain including intermediate certificates in the correct order.
🔍 Self-Signed Certificate
Issue: Certificate is not issued by a trusted Certificate Authority.
Solution: Replace with a certificate from a trusted CA like Let's Encrypt, DigiCert, or other recognized authorities.
Frequently Asked Questions
What is an SSL certificate?
An SSL/TLS certificate is a digital certificate that authenticates a website's identity and enables encrypted connections between browsers and servers.
How often should I check my SSL certificate?
Check certificates regularly, especially before expiration. Set up automated monitoring to alert you 30-60 days before expiry to ensure uninterrupted service.
What's the difference between SSL and TLS?
TLS (Transport Layer Security) is the successor to SSL (Secure Sockets Layer). Modern certificates use TLS, but "SSL certificate" remains the common term.
Do I need a wildcard certificate?
Wildcard certificates (*.example.com) are useful if you have multiple subdomains. For single domains or specific subdomains, standard certificates are sufficient.
How does this tool compare to others?
Our checker focuses on certificate correctness and essential security signals for fast, actionable feedback. For exhaustive cipher analysis, consider dedicated SSL server tests.
Need More Security & SEO Tools?
We have a complete suite of security and web analysis tools for comprehensive website optimization.
View All Tools →