JSON Formatter & Validator

Format, validate, and beautify JSON data online. Instantly detect syntax errors, pretty-print nested objects, and minify JSON with this free browser-based tool.

How to use

  1. Paste your raw JSON data into the input editor on the left side.
  2. Click Format to pretty-print the JSON or Minify to compress it.
  3. Review any validation errors highlighted inline with line numbers.
  4. Copy the formatted output or download it as a .json file.

FAQ

Is my JSON data sent to a server for formatting?

No. All formatting and validation happens entirely in your browser. Your data stays on your device and is never transmitted to any server.

What size JSON can this tool handle?

The tool processes JSON of several megabytes comfortably since all parsing runs client-side in your browser. Very large files may depend on your device memory.

Can I validate JSON with comments or trailing commas?

Standard JSON does not allow comments or trailing commas, so the validator will flag them as errors. All processing stays in the browser, letting you fix issues instantly.