SSL Checker
Check any domain's SSL certificate: issuer, expiry date, TLS version, security grade and hardening recommendations.
Check a certificate
Frequently asked questions
What does this SSL checker verify?
It completes a real HTTPS handshake with the domain, then reads the public certificate transparency record to report the issuer, validity window, covered hostnames and security headers.
What happens when a certificate expires?
Browsers show a full-page security warning and most visitors leave immediately. Automate renewal with ACME (Let's Encrypt) so it can never lapse.
What is HSTS?
HTTP Strict Transport Security tells browsers to only ever contact your site over HTTPS, which blocks downgrade and cookie-stealing attacks on public Wi-Fi.
Which TLS version should I use?
Serve TLS 1.3 with TLS 1.2 as a fallback and disable TLS 1.0 and 1.1 entirely — they are deprecated and fail modern compliance audits.