JSON Validator With Error Messages & Line Numbers
Free online JSON validator that shows exact error messages with line and column numbers. Find and fix JSON syntax errors instantly.
Why You Need Error Messages
Most JSON validators just say "invalid" without telling you where the error is. Our JSON Formatter shows the exact error message with line number and column, so you can jump straight to the problem.
How It Works
The validator uses the browser's native JSON.parse() which provides detailed error information. We extract the position from the error message and calculate the line and column number.
Try It Free
Use our free online tool — 100% client-side, no data leaves your browser.
Open JSON Validator