JSON tools that never see your data.
JsonKit is a collection of 30 free JSON utilities that run entirely in your browser. Paste a production payload, an access token or a customer record — none of it is uploaded, logged or stored. It just works, the second the page loads.
Most JSON tools upload your data. We didn't want to.
The quickest way to format or convert a blob of JSON is usually to paste it into the first website that turns up. But those tools send whatever you paste to a server to process it — which is a real problem when the blob is a production response, an auth token or someone's personal data.
JsonKit takes the opposite approach. Every tool is written to run locally, so your input is processed on your own machine and never transmitted anywhere. That makes it faster — there's no network round trip — and it means there is genuinely nothing for us to log, leak or sell. It's the toolkit we wanted for ourselves: private by default, instant, and free.
What JsonKit stands for
Your data never leaves the tab
Every tool runs on your device with JavaScript. Disconnect from the internet and they keep working — there is simply no server to send your JSON to.
Results as you type
No submit buttons and no round trips. Format, validate, convert and diff update live, with errors flagged by line and column.
Built for flow
Press ⌘K to jump between tools, run with ⌘↵, copy with ⌘C. The whole toolkit is usable without touching the mouse.
No signup, no paywall
All 30 tools are free with no file-size limit and no ads. Nothing is gated behind an account, because there are no accounts.
What's inside
Thirty tools across four families, each on its own page and pre-filled with sample data.
Format
Prettify, minify, escape and repair JSON so it's readable — or compact — in a click.
Validate
Check JSON against a schema, diff two payloads line by line, and decode JWTs to inspect their claims.
Convert
Move JSON to and from CSV, YAML, XML and TypeScript types without leaving the browser.
Query & Generate
Pull values out with JSONPath, and generate mock data or a JSON Schema from an example.
Found a bug or have an idea?
JsonKit gets better on feedback. Tell us what's broken or what you wish it did.