Effective date: 21 September 2026
Add-on: Ruler Pro (@ruler-pro) for Mozilla Firefox

Ruler Pro is a screen overlay (ruler and pixel grid). It does not collect, sell, share, or transmit personal information.


None. We do not collect names, emails, browsing history, website content, location, payment data, or analytics. There are no accounts, servers, ads, or trackers.

The add-on declares Firefox data-collection permission none.


Firefox storage is used only locally on your computer to remember overlay settings, for example:

• ruler visibility, position, length, thickness, rotation, opacity, units, theme, lock, and snap options
• grid visibility, spacing, colors, labels, crosshair, and related display options

This data never leaves your browser. We cannot read it. Clearing the add-on’s data or uninstalling Ruler Pro removes it (subject to how Firefox stores extension data in your profile).


Ruler Pro requests access to websites so the ruler and grid can sit on the page like a physical ruler on the screen, on every normal tab.

The overlay does not read the page, scrape content, inject ads, or send URLs or page text anywhere. Privileged Firefox pages (such as about: pages) are not overlaid.


| Permission | Why |
|---|---|
| storage | Save your ruler and grid preferences on this device |
| Access to all websites (<all_urls>) | Draw the overlay on regular tabs |

Keyboard shortcuts (Alt+Shift+R, Alt+Shift+G, Alt+Shift+H) are handled by Firefox on your device only.


No third-party analytics, advertising, crash reporting, or CDNs are used. The add-on does not load remote scripts.


Ruler Pro is a measurement tool and does not knowingly collect data from anyone, including children.


If this policy changes, we will update this document and the date above. Continued use after an update means you accept the revised policy.


Questions about this policy: use the support or email address listed on the Ruler Pro page on addons.mozilla.org.