Specsheet — Design QA Toolkit

Inspect fonts, measure spacing, pick colors, overlay grids and resize the viewport. One keyboard-first toolkit for design QA.

Specsheet replaces a drawer full of design extensions with one fast, keyboard-first toolbar. Inspect type, measure spacing, check contrast, overlay a layout grid and preview screen sizes, then get out of the way with a single key. FONT INSPECTOR • Hover any text to see the font that is actually rendering, not just the first name in the CSS stack • Click to pin a card with size (px and rem), weight, line height, letter spacing and color • Built-in WCAG contrast check (AA and AAA) against the real background • See where a font comes from: Google Fonts, Adobe Fonts, next/font, installed or system • Copy any value, or the whole block as CSS MEASURE • Hover any element to see its size, padding and margin • Click one element, then hover another to see the spacing between them • Hold Option/Alt to see the spacing to the parent element • Drag to draw a ruler box that snaps to element edges • Drop vertical and horizontal guides with V and H, nudge them with the arrow keys • Walk the DOM with the arrow keys EYEDROPPER • Pick any pixel on screen and the hex code goes straight to your clipboard • Pick two colors to get their contrast ratio LAYOUT GRID • A responsive 4 / 8 / 12-column grid, or set your own columns, gutter, margin and max width • Optional 4px or 8px baseline grid SCREEN SIZES • Phone, tablet, desktop and Tailwind breakpoint presets, plus your own sizes • Sizes the viewport exactly, the way CSS media queries see it • Portrait/landscape, window positioning and recent sizes • Star your favorites and cycle through them with one shortcut BUILT FOR THE KEYBOARD • Alt+Shift+D: toggle Specsheet (⌥⇧D on Mac) • Alt+Shift+F / M: font inspector or measure; press again to exit • Alt+Shift+R: next screen size • Esc steps back one thing at a time; Shift+Esc closes everything • Press ? at any time to see every shortcut PRIVATE BY DESIGN Specsheet collects no data, has no analytics and makes no network requests. It only runs on a page when you open it there. Made by Polite Owl, a brand of Observant Systems.