Tools › Developer tools

JSON formatter and validator

Format, minify and validate JSON, including against a JSON Schema. Large files are parsed in a background thread and never leave your device.

Input 1 line · 115 B

{"user":{"id":4021,"name":"Nibbo","pro":true,"tools":["compress-video","json"],"limits":{"fileGb":3,"batch":null}}}

Result

Validate against a JSON Schema

How it works

Your JSON is parsed by the browser itself. Files over 2 MB go to a background worker, so the page stays responsive.
Errors point to the exact line and column, and the cursor jumps there.
Schema validation uses Ajv, the same validator most Node.js APIs run in production.

Is it safe to paste production data?

Yes. Nothing is sent anywhere: the page has no server that could receive it. Open DevTools and watch the Network tab while you format.

How big can the file be?

Hundreds of megabytes work on a typical laptop. The limit is your device memory, not ours.