JSON Formatter & Validator

Paste JSON to pretty-print it with your preferred indentation, validate syntax with precise error locations, or minify it to one line.

100% client-side Free forever No sign-up

Input

Output

Runs 100% in your browser — nothing is ever uploaded.

What is JSON Formatter?

Format, beautify, validate and minify JSON online. Instant syntax-error detection with line numbers. 100% in your browser — your data never leaves your device. Paste your content, get an instant result, and copy or download the output with a single click. No installation, no account and no upload: the whole process happens client-side in your browser, which keeps your data 100% private.

How to use JSON Formatter

Open JSON Formatter — it loads instantly and needs no sign-up.
Paste or type your input into the editor (or press Sample to try an example).
Adjust the available options if needed and press the action button.
Copy the result with one click or download it as a file.

Frequently asked questions

Is JSON Formatter really free?

Yes — JSON Formatter is 100% free with no limits, no watermarks and no registration. You can use it as often as you like, on as many files or inputs as you need.

Is my data safe when I use JSON Formatter?

Absolutely. JSON Formatter runs entirely in your browser using JavaScript — your input is processed on your own device and is never uploaded to any server.

Does JSON Formatter work on mobile devices?

Yes. JSON Formatter works in any modern browser on desktop, tablet and mobile (Chrome, Firefox, Safari, Edge) — there is no app to install.

Is my code uploaded to a server?

Never. Every CodeKit tool runs entirely in your browser with JavaScript. Your code is processed on your device and never touches a network — it even works offline once the page is loaded.

Are these tools really free?

Yes — 100% free, no sign-up, no limits, no watermarks. We keep the site running with minimal, non-intrusive ads.

Is there a file or size limit?

No hard limit. Because processing happens on your machine, the only constraint is your device’s memory. Files of several megabytes work fine.