RulerSNX — Ruler & Guides by SNX Solutions
Rulers, guides and markers over any webpage to check alignment, spacing and layouts locally.
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About this extension
RulerSNX brings pixel rulers and draggable guides to your browser. Check alignment, spacing and layout directly on any normal webpage.
Features:
• Pixel rulers along the top and left edges.
• Draggable guides with position readouts and color selection.
• Rectangles and circles for marking areas.
• Auto-hiding rulers that stay out of your way.
• Guides, markers and settings stored locally per website.
• Touch-friendly grab areas.
How to use: Open a normal webpage, click the RulerSNX toolbar icon and choose Activate. Drag a line from a ruler. Select an item and press Delete to remove it. Draw markers with Shift+drag or the Mark button.
This listing is available in English and German. Guides stay aligned to the browser window while you scroll. Browser-protected pages such as about: pages and the Add-ons Store do not allow overlays.
Privacy: No network requests, tracking or data transfer. RulerSNX uses temporary access to the active tab after you choose to activate it. It does not request permanent access to all websites. Guides, markers and settings are stored locally, separated by website hostname.
A tool by SNX Solutions. Source code under the MIT license: https://github.com/senexsnx/rulersnx
Features:
• Pixel rulers along the top and left edges.
• Draggable guides with position readouts and color selection.
• Rectangles and circles for marking areas.
• Auto-hiding rulers that stay out of your way.
• Guides, markers and settings stored locally per website.
• Touch-friendly grab areas.
How to use: Open a normal webpage, click the RulerSNX toolbar icon and choose Activate. Drag a line from a ruler. Select an item and press Delete to remove it. Draw markers with Shift+drag or the Mark button.
This listing is available in English and German. Guides stay aligned to the browser window while you scroll. Browser-protected pages such as about: pages and the Add-ons Store do not allow overlays.
Privacy: No network requests, tracking or data transfer. RulerSNX uses temporary access to the active tab after you choose to activate it. It does not request permanent access to all websites. Guides, markers and settings are stored locally, separated by website hostname.
A tool by SNX Solutions. Source code under the MIT license: https://github.com/senexsnx/rulersnx
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More information
- Add-on Links
- Version
- 1.4.2
- Size
- 34.04 KB
- Last updated
- 10 days ago (Sep 19, 2026)
- Related Categories
- License
- MIT License
- Privacy Policy
- Read the privacy policy for this add-on
- Version History
- Add to collection
• RulerSNX requires Firefox 140 or newer. Activate the current Firefox release from the extension popup.
• Open a normal website first. Firefox protects internal pages such as about:addons and the Add-ons Store; overlays cannot be shown there.
• After reloading a page, activate the overlay again. Locally saved guides and markers are restored.
• Guides are aligned to the browser window and remain in place while you scroll. Saved settings are stored per website hostname.
• Draw a marker with Shift+drag or by selecting Mark.
Report bugs or send feedback: info@snxcloud.de. Please include your Firefox version and the steps to reproduce the issue.