SSL Certificate Checker

Check SSL/TLS certificate details, chain, and security configuration for any domain.

ℹ SSL certificate details require a server-side lookup. This tool shows a demonstration of the expected output format. For production monitoring, use tools like Let's Encrypt, SSL Labs, or a certificate monitoring service.

About SSL/TLS Certificate Checking

SSL/TLS certificates are digital documents that authenticate a website's identity and enable encrypted HTTPS connections. Every certificate has an expiration date — typically 90 days to 2 years. An expired certificate causes browsers to display scary security warnings, breaking user trust and potentially blocking all access to your website.

Certificate monitoring is a critical operational practice. Certificate expiry is a common cause of unexpected outages — many high-profile companies including LinkedIn, Spotify, and Microsoft Azure have experienced downtime from expired certificates. Automated monitoring with alerts at 30, 14, and 7 days before expiry is a DevOps best practice.

Beyond expiry, SSL checkers verify the certificate chain is complete and trusted, the domain name matches the certificate's Common Name or Subject Alternative Names, the cipher suites and TLS version are current (TLS 1.2+), HSTS is enabled, and certificate transparency logs show no unauthorized issuances.

FAQ

How often do SSL certificates expire?
Since September 2020, the maximum validity period for publicly trusted certificates is 398 days (~13 months). Let's Encrypt certificates expire every 90 days and auto-renew with certbot. Most CA-issued certificates are for 1 year. Always set up monitoring and auto-renewal.
What happens when an SSL certificate expires?
Browsers display a "Your connection is not private" warning, preventing users from accessing your site. Most users will not proceed past this warning. Search engines may de-rank sites with certificate errors. APIs will fail with SSL errors. Revenue and reputation damage can occur within hours.

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