Format and validate JSON online

Format, validate and minify JSON entirely in your browser with this free online JSON formatter. Paste your data to pretty-print it with 2-space, 4-space or tab indentation, instantly catch syntax errors with the exact error message, or minify JSON down to the smallest possible string. The JSON beautifier and validator run 100% client-side, so nothing is ever uploaded and your data stays private. When you are done, copy the clean, formatted or minified output with one click.

🔒 100% private — files never leave your device

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How to use

  1. Paste or type your JSON into the input box.
  2. Choose an indent size: 2 spaces, 4 spaces or Tab.
  3. Click Format to beautify, Minify to compress, or Validate to check it.
  4. Copy the formatted or minified JSON output to your clipboard.

Frequently asked questions

What is the difference between Format and Minify?

Format pretty-prints your JSON with line breaks and indentation so it is easy to read; Minify strips all whitespace and newlines to produce the smallest possible single-line JSON string.

What does the Validate button do?

Validate parses your JSON and tells you whether it is valid. If there is a syntax error, it shows the exact error message and position so you can find and fix the problem.

Is my JSON uploaded or stored anywhere?

No. All parsing, formatting, validation and minifying happen locally in your browser using your device's own JavaScript engine, so your JSON never leaves your computer.

What indentation options are supported?

You can pretty-print JSON with 2 spaces, 4 spaces or a Tab character per level, matching the style guides used by most editors and projects.

Is there a size limit on the JSON I can format?

There is no fixed limit. Processing runs entirely in your browser, so the practical ceiling depends on your device's available memory; typical files of a few MB format instantly.

Does it work offline and on mobile?

Yes. Because everything runs client-side, the JSON formatter works on phones, tablets and desktops in any modern browser, and continues to work once the page has loaded even without a connection.

About this tool

Beautify, validate or minify JSON with adjustable indentation. Paste your data, fix syntax errors instantly and copy the result. Runs fully in your browser — nothing is uploaded.

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