Format, minify and validate JSON instantly. Free tool for developers.
Paste raw JSON — an API response, a log line, a config file — and the tool validates it instantly. If it's valid, it's formatted with readable indentation; if it isn't, you're told where the problem is (a trailing comma, an unclosed quote, a missing brace). You can also minify it to shrink its size before sending or storing it.
All processing happens in your browser, so you can inspect responses containing sensitive data without uploading them to a third-party service. There are no request limits and no sign-up. And with indented output you spot nested structures, empty arrays or wrongly typed fields at a glance.
Debugging an API response that doesn't match what your frontend expects, reviewing a package.json or config file before committing, cleaning up JSON copied from the browser console, or preparing a readable payload to document in a ticket or wiki.
Remember JSON allows neither comments nor trailing commas: if your editor accepts them, you're probably writing JSON5 or JSONC. Use the indented version to read and debug, and the minified one to send over the wire. And before pasting production data, check it contains no tokens or personal data that shouldn't travel.
No. Formatting and validation run entirely in your browser, so the data never leaves your machine.
No hard limit; the practical ceiling is your browser's memory. Multi-megabyte files may take a few seconds.
The usual causes are trailing commas, single quotes instead of double quotes, and comments, none of which the JSON standard allows.
Yes. You can switch between the indented version, meant for reading, and the minified one, meant for transmitting.
Yes, completely free, with no sign-up and no usage limits.