DEV3 Free Readability Score Checker — Source Code (React + Tailwind)

Source code of the DEV3 Readability Score Checker, a client-side readability scorer with Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, SMOG and Coleman-Liau plus highlighting of long sentences, passive voice and adverbs.

Free download: sign in to any DEV3 account and click Download ZIP. Try it live: https://dev3.tech/tools/readability-score-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

• Five standard formulas and an averaged grade
• Heuristic English syllable counter
• Overlapping highlights for long sentences, passive voice and adverbs
• Draft kept in localStorage

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.
• English only; syllable counting is a heuristic.