Redline

About

Stop squinting at your layouts on the web. Redline offers a shortcut to rulers and properties of any site.

Redline is a lightweight, privacy-respecting layout debugger for web developers.

Activate the inspector with a click or keyboard shortcut and Redline overlays your page with the tools you actually need while debugging visual issues:

Alignment guides that snap to neighboring elements so you can see exactly where things line up — and where they don't.

Padding and margin visualization on the element you're hovering, with pixel labels.

On-page rulers for measuring distances and double-checking spacing.

DOM layer navigation so you can step up and down the element tree without leaving the page.

A draggable, collapsible floating button so the inspector is always one click away — and out of your way when it isn't.

Keyboard shortcuts:
Alt + Shift + R — toggle inspection mode
Ctrl/Cmd + Shift + L — alternate toggle (if another extension claims the first one)

Privacy:
Redline runs entirely locally in your browser. It does not transmit any data to remote servers, does not include analytics, tracking, or advertising, and does not load any remote code. The only thing it stores is a small amount of UI state (floating button position and visibility) via chrome.storage.local on your own device.

Built for developers who want a fast, focused alignment and layout debugging tool that gets out of the way.