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
Inspects your site's X.509 certificate and presents an actionable report. Validates expiration, issuer trust, chain order, SAN/hostname match, and supported TLS versions.
How It Works
- 1Enter a hostname (e.g., example.com)
- 2Opens TLS connection with SNI on port 443
- 3Validates certificate chain, expiry, and security headers
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
Troubleshooting Common SSL Issues
Certificate Expired
Renew immediately and set up auto-renewal monitoring.
Hostname Mismatch
Issue a new certificate with correct SAN entries or use wildcard certificates.
Untrusted Issuer
Install the complete certificate chain including intermediates in correct order.
Self-Signed Certificate
Replace with a certificate from a trusted CA like Let's Encrypt or DigiCert.
Frequently Asked Questions
What is an SSL certificate?
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 regularly, especially before expiration. Set up automated monitoring 30-60 days before expiry.
What's the difference between SSL and TLS?
TLS is the successor to SSL. Modern certificates use TLS, but "SSL certificate" remains the common term.
Do I need a wildcard certificate?
Useful for multiple subdomains. For single domains, standard certificates are sufficient.