JSON Formatter & Validator — Free Online Tool

Paste JSON to format, validate, minify, or view as a tree — entirely in your browser.

How It Works

  1. 1Upload your file by dragging it into the drop zone or clicking to browse.
  2. 2Adjust the quality slider to balance file size and visual fidelity (optional).
  3. 3Click Download to save your converted file.

About JSON Formatter

Working with JSON? This tool formats messy JSON into readable, indented output with syntax highlighting and line numbers. It validates your JSON and shows clear error messages for invalid input. Toggle between formatted and minified views with one click. You can also view your data as a collapsible tree. Everything runs in your browser — no data is sent to any server.

Frequently Asked Questions

Is my JSON data sent to a server?

No. All formatting happens in your browser using JSON.parse and JSON.stringify. No data leaves your device.

What's the difference between Format and Minify?

Format adds indentation and line breaks for readability. Minify removes all whitespace to produce the smallest possible output — useful for APIs and configuration files.

Can it handle large JSON files?

It works well for JSON up to a few megabytes. Very large files may cause the browser tab to slow down due to rendering the formatted output.

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