This free online tool helps format and validate JSON data. Paste your JSON string to check syntax and beautify the output.
Example JSON for Testing:
{
"name": "John Doe",
"age": 30,
"isStudent": false,
"address": {
"street": "123 Main St",
"city": "New York",
"zipcode": "10001"
},
"hobbies": [
"reading",
"swimming",
"coding"
],
"contact": {
"email": "john@example.com",
"phone": null
}
}
Common JSON Syntax Errors:
- Missing Quotes: All keys and string values MUST use double quotes
- Trailing Commas: Do not add a comma after the last item in objects/arrays
- Comments: Standard JSON does not support comments. Remove them before validating
- Data Types: Use correct literals: true, false, null (lowercase)
Tip: Copy the example JSON above to test the formatter, then try with your own data.
Note: This tool validates standard JSON. Results are approximate.