apiverve_sslchecker

https://github.com/apiverve/sslchecker-API

SSL Checker is an SSL certificate API that connects to a website and checks its live certificate in seconds. It returns the certificate details, whether the chain verifies to a trusted root and matches the hostname, the negotiated TLS version and cipher, HSTS and OCSP stapling, plus expiry signals: valid or expired, days until expiry, expiring soon and self-signed.