Your page stays on your device.

Signal Check is built to inspect potentially sensitive work pages without sending their contents anywhere. The extension has no server component, analytics, advertising, account system, or remote code.

What the extension processes

When you press “Check this page,” the extension temporarily captures the visible tab and reads visible page elements. It downsamples the screenshot in browser memory to compare colors, checks likely legend and status marks, and injects the result overlay into that tab. The screenshot and page text are not uploaded or written to storage.

What is stored

• Your selected comparison: deutan, protan, or tritan.
• The count and time of your most recent check, so the popup can show useful continuity.

This information stays in the browser’s local extension storage. Use “Clear last check” in the popup or remove the extension to delete it.

Permissions

Active tab and scripting let Signal Check inspect only the page you explicitly check and show the overlay. Storage remembers the comparison and last result locally. There are no broad site-access host permissions.

Website data

This website does not use cookies, analytics, tracking pixels, third-party fonts, or embedded third-party scripts. Standard web-host access logs may briefly contain technical request information under the host’s operational policies.

Contact and changes

Questions or reports can be opened in the project’s public issue tracker. Material policy changes will be dated on this page. Signal Check is intended for general audiences and does not knowingly collect personal information from children.