Data converters
JSON Validator
Check JSON syntax and get clear error messages. Nothing you enter leaves your browser.
Your result will appear here.
What this tool does
About the JSON Validator
Check JSON syntax and get clear error messages. It is useful when data needs to move between spreadsheets, APIs, configuration files, databases, or documentation without retyping records.
The tool checks the supplied value and reports validation details so you can correct the source rather than guessing where it failed.
How to use it
- Paste JSON in the input pane. Use the example button if you want to see the expected syntax.
- Review the input for the structure shown in the example. Then select “Validate JSON.”
- Inspect the result for warnings or structural differences, then copy it into the destination system.
Practical example
Start with a known input
Try this sample input:
{"valid": true}
Select “Validate JSON” and compare the result with the source before using it elsewhere. What to know about the result
- JSON preserves nested objects, arrays, numbers, booleans, and null values, but it requires quoted property names and does not allow comments.
- Processing happens in this browser. Your entered text and selected files are not sent to FormatCalc for conversion.
Common questions
Using the JSON Validator
Is the JSON Validator free to use?
Yes. FormatCalc's JSON Validator is free to use with no account required.
Is my data private when I use the JSON Validator?
Yes. This tool processes your input locally in your browser. FormatCalc does not upload or store what you enter.
How do I use the JSON Validator?
Paste or type your input, select any available options, and choose Validate JSON. You can then copy the result.
What should I check before using the result?
JSON preserves nested objects, arrays, numbers, booleans, and null values, but it requires quoted property names and does not allow comments. Processing happens in this browser. Your entered text and selected files are not sent to FormatCalc for conversion.