Jsony

JSON, fast and local. Fast, private developer tools for JSON and beyond. Everything runs in your browser — your data never leaves the page.

Live at jsony.dev.

What's here

• /json-formatter — anchor tool: format, validate, and explore JSON. Handles 50MB payloads without freezing.
• More tools coming: JSON to CSV, JSON Diff, JWT Decoder, Base64.

Why

Existing free JSON tools are slow on large payloads, ad-cluttered, send your data to servers, and have weak UX for exploring complex JSON. Jsony does all the work in your browser — no uploads, no tracking, no cookie banner. The source is here so you can verify that.

Stack

Next.js 16 (App Router) with static export, React 19, Tailwind 4, TypeScript strict mode. Hosted on Cloudflare Pages.

Local development

npm install
npm run dev

Then open http://localhost:3000.

Project posture

This is a personal project. Issues are welcome but there's no SLA — I'll get to them when I can. PRs are reviewed when I have time. If you find a parsing edge case or a perf regression, a fixture in the issue helps a lot.

License

MIT.