JSON Formatter & Validator Online
Use this free online JSON Formatter & Validator tool to format, validate, and minify JSON data instantly. All processing is done locally in your browser.
Formatted output appears here
How it works & FAQ
Why this is secure?
All JSON processing runs entirely in your browser's JavaScript engine. Your JSON data is never uploaded or transmitted to any server.
Step-by-Step Guide
- 1Paste your JSON string into the input field.
- 2Click 'Format' to beautify with indentation, or 'Minify' to remove all whitespace.
- 3Copy the formatted output using the copy button.
Frequently Asked Questions (FAQ)
Does this detect JSON errors?
Yes. Invalid JSON is highlighted with an error message showing exactly where the syntax problem is.
Is there a size limit for JSON input?
No server limit. Very large JSON files (1MB+) may take a moment to parse, limited only by your device's memory.
Can I validate JSON without formatting it?
Yes. Any input you paste is validated live as you type — a green indicator means valid, red means there's a syntax error.
Your JSON is processed entirely in browser memory. No data is sent anywhere.