JSON Formatter & Validator
Beautify messy JSON, minify it for production, or validate it with exact error locations. Everything runs locally in your browser.
How to use
- Paste your JSON into the input box on the left.
- Click Format to pretty-print with 2-space indentation, or Minify to strip all whitespace.
- Click Copy output to grab the result. Invalid JSON shows the exact line and column of the error.
Frequently asked questions
Is my JSON data uploaded to a server?
No. This tool runs entirely in your browser using JavaScript. Your JSON is never sent to any server — you can verify this by opening your browser's network tab.
What is JSON formatting?
JSON formatting (also called beautifying or pretty-printing) adds indentation and line breaks to compact JSON so it is readable by humans. Minifying does the opposite: it removes all unnecessary whitespace to produce the smallest possible valid JSON.
Why does my JSON fail validation?
The most common causes are trailing commas, single quotes instead of double quotes, unquoted keys, or comments — all of which are invalid in strict JSON. This tool shows the exact line and column of the first error to help you fix it.
Is there a size limit?
There is no hard limit. Because formatting happens locally in your browser, the practical limit depends on your device's memory. Files of several megabytes are typically handled without issue.