SSL Certificate Checker — Verify SSL & HTTPS Free Online

An SSL/TLS certificate encrypts the connection between a user's browser and the web server. It also verifies the identity of the server, ensuring users are not connecting to an impersonator. Sites with SSL show a padlock in the browser address bar and use HTTPS.

HTTPS (HyperText Transfer Protocol Secure) is HTTP over an encrypted TLS connection. Google uses HTTPS as a ranking signal, browsers mark HTTP sites as 'Not Secure', and form data (passwords, credit cards) is only safe to transmit over HTTPS.

HSTS (HTTP Strict Transport Security) is a security header that tells browsers to only connect to a site over HTTPS, even if the user types http://. It prevents SSL stripping attacks and forces encrypted connections.

A redirect from HTTP to HTTPS means the server automatically forwards users who visit http://yourdomain.com to https://yourdomain.com. This is a security best practice and ensures all traffic is encrypted.

The checker uses a public CORS proxy. Some domains block proxy requests or are slow to respond. For definitive certificate information including issuer, expiry date, and trust chain, use a dedicated tool like Qualys SSL Labs.

This means the certificate was issued by a CA not included in major browsers' trusted root stores — either self-signed, expired CA, or a mis-issuance. Users will see security warnings. Replace with a certificate from a trusted CA like Let's Encrypt.

Renew at least 30 days before expiry. Let's Encrypt certificates are valid for 90 days and should be renewed every 60 days. Most commercial CAs allow renewal 30—90 days before expiry without losing remaining days.