Is this JSON formatter completely free?

Yes, 100% free with no limits. No account, no subscription, no hidden charges. Format as many JSON files as you want.

Does it validate JSON syntax?

Yes. It validates your JSON instantly and shows the exact error location with line numbers if the JSON is malformed.

Does my data get sent to any server?

No. All formatting and validation happens entirely in your browser using JavaScript. Your data never leaves your device.

Can I view nested JSON as a tree?

Yes. The tool provides a collapsible tree view where you can expand and collapse nested objects and arrays to explore large JSON structures easily.

What indentation options are available?

You can choose between 2-space, 4-space indentation, or minified (compressed) output. The default is 2-space for readability.

Does it work on mobile phones?

Yes, it works on any modern browser including Chrome on Android and Safari on iPhone. The interface is fully responsive.

✓ No upload✓ Tree view✓ Free forever

Free JSON Formatter & Validator Online

Paste raw JSON to format, validate, and explore with a collapsible tree view. Trusted by developers worldwide.

JSON Input

Formatted Output

How to use JSON Formatter

Three steps. Under 10 seconds.

📋

Paste your JSON

Copy raw JSON from your API response, file, or editor and paste it into the left panel.

⚡

Click Format

Hit the Format button. The tool validates your JSON and formats it with your chosen indentation.

🌳

Explore or copy

Switch to tree view to explore nested data, or copy/download the formatted output.

How JSON Formatter works

This tool uses your browser's built-in JSON.parse() engine to validate your input. If the JSON is valid, it reformats it using JSON.stringify() with your chosen indentation level. If the JSON is malformed, the browser returns the exact character position of the error, which the tool maps to a line number for easy debugging. The tree view is built by recursively walking the parsed object and rendering collapsible nodes for each key. Everything runs client-side — your data never leaves your device.