DEV3 Free Colour Palette and Contrast Checker — Source Code (React + Tailwind)

Source code of the DEV3 Colour Palette and Contrast Checker, colour maths and accessibility checks: WCAG contrast ratios, a nearest passing colour, colour-space conversion and palette export.

Free download: sign in to any DEV3 account and click Download ZIP. Try it live: https://dev3.tech/tools/color-palette-contrast-checker shows the finished tool running.

What is in the download

• A standalone Vite + React + TypeScript + Tailwind CSS project: src/tool holds the tool, shared pieces sit beside it
• package.json with exact versions plus a lockfile, so npm ci works
• README.md (run, build, embed in Next.js or plain React) and an MIT LICENSE

What the code does

• Contrast ratio with AA and AAA results for normal and large text
• HEX, RGB, HSL, HSV and OKLCH conversion
• Suggests the closest foreground that passes
• Palette export as CSS variables, Tailwind JSON or SCSS

Tech stack

React 19, TypeScript, Vite, Tailwind CSS 4.

Install and customise

The How to install and How to use tabs list the steps. In short: unzip, npm ci, npm run dev, then copy the tool folder into your own app if you want to embed it.

Good to know

• A browser-only tool: there is no backend or database in the code.