Box Detector

CSS Box Detector Chrome Extension

Box Detector is a minimal yet highly practical CSS box detector Chrome extension designed for frontend developers and UI designers. It instantly outlines and highlights every box model layer (margin, border, padding, content) on any webpage — giving you a fast and visual way to inspect layout issues, spacing, or element nesting.

Think of it as a simpler, faster alternative to using DevTools for box model inspection. Once enabled, you get real-time outlines as you hover or click on elements, saving time when debugging spacing problems, misaligned elements, or broken layouts.

Built and maintained by the team behind MLKV, Box Detector is fast, privacy-respecting (no data collection), and requires no setup — install and use immediately.

Key Features – CSS Box Detector Chrome Extension

• 🔲 Visual CSS Box Model Detection – See margin, border, padding, and content boxes directly on the page
• 🖱️ Hover or Click to Inspect – Choose the mode that fits your workflow
• ⚡ Fast and Lightweight – Zero performance drag; works instantly
• 🧩 Toggle Activation – Activate only when needed
• 🔐 Privacy-First – No tracking, no external requests

Who Is It For?

Perfect for:

• – Frontend developers debugging layout or spacing
• – Designers inspecting live pages
• – QA testers verifying visual consistency
• – Developers tired of opening DevTools for small layout checks

Why It’s Useful – CSS Box Detector Chrome Extension

Box Detector gives instant feedback on how boxes behave in the DOM. No more trial-and-error debugging. It’s especially helpful in complex layouts where margin/padding collisions or nested elements cause visual bugs. Lightweight, distraction-free, and straight to the point.