SSL Checker

What is the SSL Checker?

The SSL Checker is an advanced online utility designed to securely inspect and verify the SSL (Secure Sockets Layer) or TLS (Transport Layer Security) certificate of any active website. It establishes a direct connection to the target server to pull real-time cryptographic details to ensure the domain is safe, secure, and properly configured for data transmission.

Common Use Cases

• Security Audits: System administrators use this tool to quickly verify that their web servers are broadcasting the correct, unexpired SSL certificates to the public.
• SEO Management: Search engines heavily penalize or delist sites with expired certificates. Webmasters use this tool to ensure their SEO rankings remain intact by preventing certificate lapses.
• Troubleshooting: IT professionals use the checker to diagnose complex chain-of-trust problems, mismatched subject alternative names (SANs), or incorrectly applied certificates after a server migration.

Key Features

Expiration Monitoring

The tool provides exact timestamps for when a certificate was issued (Valid From) and precisely when it expires (Valid To). It automatically calculates and displays the exact days remaining until expiration, giving you ample time to renew.

Issuer Verification

It clearly extracts the Certificate Authority (CA) that issued the certificate (e.g., Let's Encrypt, DigiCert, GlobalSign). This helps you guarantee that the certificate is backed by a recognized and trusted industry provider.

Signature Type & Serial Decoding

The tool analyzes the exact X.509 certificate blueprint, returning granular details like the cryptographic signature type (e.g., ecdsa-with-SHA384) and the unique serial number natively assigned to your certificate.

Privacy & Security

We prioritize your privacy and security. While this tool must reach out to the target server over the internet to securely fetch the public X.509 certificate, we do not log, store, or monitor the domains you query. All operations are strictly read-only; no data is modified or retained.

Technical Details

The SSL Checker works by initializing a sterile, independent stream context utilizing PHP's underlying OpenSSL implementation. It establishes a secure socket connection on port 443 with the target domain. Upon successful handshake, it captures the raw peer_certificate resource, parses the dense ASN.1 encoded X.509 format, and maps the arrays into human-readable data points.