Mixed Content & Secure Context HTML Auditor

When an HTTPS page loads resources over HTTP, browsers silently block active content (scripts, stylesheets, iframes) and flag the page as "Not Secure." Paste your HTML and find every insecure reference — classified by severity — then export an HTTPS-fixed version in one click.

Privacy, Security & Web APIs 100% Local Your HTML is parsed in memory. No resources are fetched.

Tool interface

Introduction

Migrating a site to HTTPS often leaves behind hardcoded http:// references buried in templates, CMS content, and legacy markup. These cause mixed-content errors that break pages and remove the secure padlock. This auditor finds every one and tells you which are dangerous.

How It Works

  • The HTML is parsed with DOMParser — no resources are actually fetched.
  • Every resource-bearing attribute is scanned: src, href, srcset, action, data, and inline/block CSS url().
  • Each http:// reference is classified as active (critical) or passive (warning).
  • A fixed HTML export replaces every insecure URL with its HTTPS equivalent.

Privacy

Your HTML is parsed entirely in your browser. No resources are fetched and no content is transmitted. No API calls, no tracking.

Limitations

  • Cannot detect mixed content injected dynamically by JavaScript after page load.
  • The HTTPS-fixed export assumes the target server supports HTTPS; verify before deploying.
  • Does not verify that each https:// URL actually resolves.

FAQ

Why do some resources break and others don't?

Browsers block "active" mixed content (scripts, stylesheets, iframes) because it can execute code and compromise the page. "Passive" content (images) is allowed but downgrades the security indicator.

Are protocol-relative URLs okay?

URLs starting with // inherit the page's scheme, so they're safe on HTTPS pages. However, explicit https:// is now preferred.

Is my HTML uploaded?

No. Everything is parsed locally in your browser. Nothing is transmitted.

Related Tools

Version and changelog

  • Version: 1.0.0
  • Last updated: August 13, 2026
  • Changelog: Initial production release.