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JSON Formatter & Validator

Paste your JSON to format, beautify, minify and validate it instantly. Free online JSON formatter that runs 100% in your browser — no data is uploaded.

json-formatter.run

What is a JSON formatter?

A JSON formatter takes raw, minified or messy JSON and rewrites it with consistent indentation and line breaks so humans can read it. JSON (JavaScript Object Notation) is the standard data format of web APIs — but servers usually send it minified into a single unreadable line to save bandwidth.

This tool also validates: it parses your input against the official JSON specification and pinpoints the exact syntax error (a missing comma, an unquoted key, a trailing bracket) instead of just saying 'invalid'. Formatting and minifying both run locally in your browser.

How to use

  1. 01Paste your raw JSON into the input box on the left.
  2. 02Click Format / Validate to beautify it, or Minify to compress it.
  3. 03If the JSON is invalid, the exact error is shown so you can fix it.
  4. 04Click Copy output to copy the result to your clipboard.

Frequently asked questions

Is my JSON uploaded to a server?
No. This tool runs entirely in your browser using JavaScript. Your data never leaves your device, which makes it safe for sensitive payloads.
What does the validator check?
It checks that your text is syntactically valid JSON according to the official specification — matching brackets, quoted keys, correct commas and value types.
What is the difference between formatting and minifying?
Formatting adds indentation and line breaks so JSON is easy to read. Minifying removes all unnecessary whitespace to make the file as small as possible for production use.
Is this JSON formatter free?
Yes, completely free with no signup, no limits and no ads blocking the tool.

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