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JSON Formatter

Format and validate JSON

About JSON Formatter

JSON Formatter parses your JSON with the browser's built-in JSON.parse and re-serializes it with JSON.stringify, entirely in your browser — nothing is uploaded to a server. Format adds 2-space indentation; Minify strips it back to a single line. Since it uses a real parser, invalid JSON is reliably caught and reported rather than guessed at.

How to use JSON Formatter

  1. 1Paste your JSON into the input box.
  2. 2Click 'Format' for readable, indented JSON, or 'Minify' for a compact single-line version.
  3. 3If the JSON is invalid, an 'Invalid JSON' error appears instead of output.
  4. 4Click 'Copy' to copy the result to your clipboard.

Frequently Asked Questions

Is JSON Formatter free to use?

Yes, it's completely free with no signup required.

Does it validate my JSON?

Yes — since it uses the browser's real JSON parser, any syntax error causes a clear 'Invalid JSON' message rather than a best-effort guess.

Does it support a tree view or syntax highlighting?

No, output is plain indented or minified text in a textarea — there's no collapsible tree view or colored syntax highlighting.

Is my data uploaded to a server?

No, formatting and minifying both happen entirely in your browser.

Tips & Tricks

  • ✓If you get 'Invalid JSON', check for common issues like trailing commas, single quotes instead of double quotes, or unquoted keys — none of which are valid JSON.
  • ✓Format and Minify are reversible: format minified JSON to read it, or minify formatted JSON to compact it back down.
  • ✓There's no file upload or download — paste JSON in and copy the result out.
  • ✓For very large JSON, formatting and minifying both run synchronously in your browser, so extremely large input may briefly freeze the page.