Text & Data
JSON Formatter & Validator
Validate, format, minify, and recursively sort JSON in your browser with precise error locations.
How to use this JSON tool
Paste or type JSON to see live validation and the exact error line and column. Choose an indentation style, then format, minify, or recursively sort keys; all processing happens in your browser.
Large integers and duplicate keys
Large integers are preserved as written with a warning because JavaScript numbers may not represent them exactly. Duplicate keys are warned about and preserved by default; you can also reject them.
Frequently asked questions
Why is a trailing comma invalid?
JSON does not allow a comma after the final object member or array item. Remove the trailing comma and try again.
How are duplicate keys handled?
The default warns and preserves duplicate members instead of silently overwriting data. You can also allow them explicitly or treat them as an error.