Loupe — Pixel-Perfect UI Inspection

Inspect, measure, and analyze any web UI. Box model, computed CSS, layout grids, rulers, color picker, responsive mode.

Loupe is a pixel-perfect UI inspection toolkit for designers and front-end developers. ■ Inspect — hover any element for its selector, box model, computed CSS, and ancestry ■ Measure — click two elements to see exact pixel distances between them ■ Layout Grid — overlay a configurable column/gutter/margin grid on any page ■ Page Rulers & Xray — pixel rulers and depth-outlined element structure ■ Color Picker — grab any color on screen with the native eyedropper ■ Find Element — locate elements by CSS selector or text ■ Tailwind Xray — highlight every element still using raw Tailwind utility classes (with a brand-prefix allowlist), so design-system components can replace them ■ Design System Profiles — load your design system's token profile and see which token every element uses, inventory your components on any page, and flag native controls that should be components ■ DS Lint & Dark-Mode Diff (Pro) — page-wide audits against your design system's rules: raw colours, rogue spacing, deprecated tokens, and colours that don't respond to your dark theme ■ Responsive Mode — preview any URL with true device emulation (viewport, touch, user agent) in a real tab, so login flows keep working ■ Figma Compare — anchor a Figma frame to your live DOM and get a per-element diff heatmap with severity grading, plus optional AI-written fix suggestions using your own Anthropic API key grading, plus optional AI-written fix suggestions using your own Anthropic API key Everything runs locally in your browser — no analytics, no data collection. The inspector toolkit and design-system profiles are free forever; the audits, Figma comparison, AI suggestions, and report export are part of Loupe Pro ($8/mo, $59/yr, or $129 lifetime, 7-day free trial). Enable it per tab with one click or Alt+Shift+K. Teams: an organisation licence unlocks Pro for everyone using your design system's profile — no individual accounts — with hosted profile auto-updates and reporting to your own endpoint. Contact the developer for commercial licensing.