TheDevKits Logo

What is an SSL Certificate Checker?

An SSL (Secure Sockets Layer) or TLS (Transport Layer Security) Checker queries a domain to retrieve the public cryptographic certificate protecting the server.

Because of browser security policies, you cannot read an arbitrary website's SSL certificate directly from client-side JavaScript.

This tool proxies the request via a Node.js backend using the native `tls` module, establishes a secure socket, and extracts the raw PEER_CERTIFICATE.

It validates the Certificate Authority (Issuer), the expiration dates, and the cryptographic fingerprints used to sign the domain.

1How to Use

  • 1. Enter a valid domain name (e.g., yourwebsite.com) without the https prefix.
  • 2. Our backend performs a handshake on port 443.
  • 3. The tool parses the X.509 certificate data strings into a readable diagnostic display.