✓ 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.

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Paste your JSON

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

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Click Format

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

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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.

Why use this JSON Formatter?

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100% private

Your data stays in your browser. Nothing is uploaded to any server, ever.

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Collapsible tree view

Explore deeply nested JSON structures with expand/collapse controls.

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Instant validation

Get error messages with exact positions — debug malformed JSON in seconds.

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Works everywhere

Responsive design works on desktop, tablet, and mobile. No app install needed.

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Works offline

Once loaded, the tool works without an internet connection.

Frequently asked questions

Is this JSON formatter free?

Yes. It is completely free with no signup or limits.

Does it validate JSON and show errors?

Yes. It validates syntax and points to the error location when JSON is invalid.

Can I minify JSON?

Yes. Switch to the minified view for compact output.

Can I view JSON as a tree?

Yes. The tree view is collapsible for easy navigation.

Is my data private?

Yes. All formatting and validation happen locally in your browser.

Can it handle large JSON files?

It works well for large documents, but extremely big files depend on browser memory.

Can I search within JSON?

Yes. Use the search box in tree view to find keys or values.

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