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🛡️ SSL Certificate Checker

Verify the validity, issuer, and expiration of a website's SSL/TLS certificate.

ℹ️ About SSL Certificate Checker

The SSL Certificate Checker is a diagnostic tool for auditing the security of web connections. Secure Sockets Layer (SSL) and its successor, Transport Layer Security (TLS), are the protocols that provide encryption and identity verification for websites (HTTPS).

This tool establishes a secure handshake with the target server and retrieves its Public Certificate. It then parses the certificate to reveal the 'Common Name' (the domain it protects), the issuing Certificate Authority (like DigiCert or Let's Encrypt), and most importantly, the expiration date. Regularly checking your certificates is vital for preventing 'Expired Certificate' warnings that can drive away visitors and break automated API connections.

📖 How to use SSL Certificate Checker

  1. 1. Enter the domain name (e.g., <code>example.com</code>).
  2. 2. Click 'Run Tool' to perform the live handshake.
  3. 3. Review the 'Days Remaining' to see if you need to renew soon.
  4. 4. Check the 'Issuer' to ensure the certificate was issued by a trusted authority.

Frequently Asked Questions

What happens when a certificate expires?

Browsers will display a prominent security warning to users, and most modern applications will refuse to connect, causing an outage for your service.

Who is the 'Issuer'?

The issuer is the Certificate Authority (CA) that verified the identity of the domain owner and cryptographically signed the certificate.

Can I check a specific port?

This tool currently checks the standard HTTPS port (443). Support for custom ports like 8443 or SMTP/STARTTLS will be added in a future update.

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