HTTPS Mixed Content Checker Tool

I built a free HTTPS and mixed content checker that helps site owners and SEOs catch security-signal issues before they become trust or crawl-quality problems.

A page can have an SSL certificate and still create trust problems. The http:// version might fail to redirect, the canonical tag might point to an insecure URL, or the page might load scripts, iframes, images, or form actions over http://.

Those issues are easy to miss because the browser may still load the page while silently blocking or warning on specific resources.

Final protocol and HTTP status checks

http:// to https:// redirect testing

Strict-Transport-Security header detection

Canonical protocol checks

HTML scan for active and passive mixed-content resources

Findings grouped by protocol, redirect behavior, HSTS, and insecure resource issues

The tool is explicit about scope. It checks the HTML it receives. It cannot see resources injected later by JavaScript, background images buried in external CSS files, or problems on pages it has not visited. That makes it useful as a first-pass QA tool without overclaiming.

This made an unglamorous but important technical check easy to run during site QA, migrations, and SEO audits.