About JsonKit

What JsonKit is

JsonKit is a toolkit of 14 free JSON utilities — a formatter, minifier, validator, diff, schema generator, JWT decoder, converters to and from CSV, YAML, XML and TypeScript, a JSONPath tester and a mock-data generator. Each tool lives on its own page, comes pre-filled with sample data, and works the moment it loads.

Why client-side

Most online JSON tools upload whatever you paste to a server to process it. That is a problem when the data is a production payload, an access token or customer information. JsonKit takes the opposite approach: every tool runs entirely in your browser with JavaScript, so your data never leaves your machine. It is faster too — there is no network round trip, and results update live as you type.

This design also means the tools keep working offline once the page has loaded, and there is genuinely nothing for us to log, leak or sell.

Free and open source

All 14 tools are free, with no signup, no file-size paywall and no ads. There is no paid tier. The project is open source under an MIT-style license, so you can read exactly how each tool works, verify the privacy claims yourself, and contribute improvements.

Built for developers

JsonKit is keyboard-friendly and fast: jump between tools, work live as you type, and copy results in a click. It is the tool you reach for when you want a clean answer in the next five seconds, on any machine, without installing anything.