Free JSON Formatter & Validator

A simple tool that formats, validates, and minifies JSON. Runs entirely in your browser — nothing is sent to a server.

Try it

Why I built this

Most JSON formatters online are bloated with ads or send your data to a server. This one runs 100% client-side — your data never leaves your browser.

How it works

It’s literally three lines of JavaScript:

// Format
JSON.stringify(JSON.parse(input), null, 2);

// Minify
JSON.stringify(JSON.parse(input));

The browser’s built-in JSON.parse() handles validation, and JSON.stringify() with the spacing parameter handles formatting. No libraries needed.