CheckMyHTTPS is a free browser extension for Firefox that enhances online security by verifying the integrity of HTTPS connections. By clicking on the extension icon, users can easily assess the security status of the website they are visiting. The extension employs a color-coded system: green indicates a secure connection, red signals a risky connection, gray means verification is impossible, and black shows that verification is in progress. This feature is particularly useful for users on open networks or in environments where SSL inspection may occur.

The extension works by comparing the security certificate provided by the site with one retrieved from an external check server. If discrepancies arise, the connection may be compromised, alerting users to potential risks. CheckMyHTTPS respects user privacy, requiring only the domain name and IP address of the visited site for verification. Users can also choose to host their own check server, providing greater control over their security checks.