Tool Kumar tool
JSON validator
Paste JSON to check whether it follows the standard syntax. Tool Kumar marks the exact line and column and offers repairs for common loose JSON.
How to use this tool
- Paste the document into the input pane.
- Read the error banner and jump to its location.
- Fix the character or choose Repair input when the issue is safe to correct.
Worked example
This sample has a trailing comma. The validator points to the comma after 36.
Input
{"name":"Ada","age":36,}Output
Invalid JSON
Line 1, column 23: Trailing commas are not allowedOptions and edge cases
- Checks objects, arrays, strings, numbers, booleans and null.
- Reports trailing commas, comments and other fixable input issues separately.
- Use the formatted view to confirm the repaired result.
Private by default
Your document stays in this browser. Tool Kumar parses, converts and creates downloads on your device, with no account or upload step.
JSON validator questions
- What does a JSON validator check?
- It checks JSON syntax, including quotes, commas, brackets, numbers and the allowed value types.
- Can it repair invalid JSON?
- It can repair common issues such as trailing commas and single quotes, then shows the result as an undoable edit.
- Where does validation happen?
- The parser runs locally in your browser. Tool Kumar does not need a server request.