SSL Certificate Checker
A real TLS connection to the site — issuer, validity period, days until expiry. No third-party API.
Frequently asked questions
What happens when a certificate expires?⌄
Visitors' browsers will show an insecure-connection warning, and some visitors will leave before the page even loads. Many certificates (Let's Encrypt, for example) are issued for just 90 days and need automatic renewal.
Does the check account for intermediate certificates?⌄
We check the leaf certificate and whether the TLS handshake passed Node.js's standard trust validation — that's enough to tell whether browsers will trust the certificate.