JSON Formatter & Validator
Paste messy or minified JSON and get it properly indented and readable, or compress it down to a single line. Invalid JSON is flagged with the exact error position so you can fix it fast. Nothing is uploaded — parsing happens entirely in your browser.
How to use
- Paste your JSON into the input box.
- Click Format to beautify with 2-space indentation, or Minify to strip all whitespace.
- If the JSON is invalid, an error message tells you exactly what is wrong and where.
- Use Copy to grab the result for your code or config file.
Frequently asked questions
Is my data sent to a server?
No. All formatting and validation runs locally in your browser using JavaScript. Your JSON never leaves your device.
What are common JSON syntax errors?
Trailing commas after the last item, single quotes instead of double quotes, unquoted object keys, and comments (JSON does not support them) are the most frequent mistakes.
What is the maximum size it can handle?
It comfortably handles files of several megabytes in a modern browser. Extremely large files may be limited by available memory.