How to use JSON Formatter
- Paste JSON, or drop a .json or .txt file into the input panel.
- Choose Format for readable indentation, Minify for compact output, or Validate for a syntax report.
- Run the operation. Check any error, then copy or download the result.
Worked examples
Use the inputs below to compare the selected mode with a known result. Loading an example replaces the current input.
Format a small API response
Input
{"order":"A-104","items":[{"sku":"PEN","qty":2}],"paid":false}Expected result
{
"order": "A-104",
"items": [
{
"sku": "PEN",
"qty": 2
}
],
"paid": false
}The nested item becomes easier to inspect. The string ID and boolean remain different data types.
Find a trailing comma
Input
{"active":true,}Expected result
Syntax error: remove the comma after true.
JSON does not permit a comma after the final member of an object. The browser may phrase its parser error differently.
Catch a duplicate field
Input
{"role":"reader","role":"admin"}Expected result
Duplicate object key: role
This tool stops instead of silently keeping the second value. Rename or remove the duplicate in the source data.
What this tool does and does not do
Text input is limited to 2,097,152 JavaScript string units; dropped text files are limited to 2 MiB. This tool rejects duplicate object keys and unsafe integer values. It does not check an API schema or preserve the original byte sequence.
Conversions run in the current browser. Input drafts are temporary; copy or download important results before leaving. See the privacy policy for the separate handling of visits and preferences.
Common questions
Does valid JSON mean the data is correct?
No. {"quantity":"two"} is valid JSON, but a receiving API may require a number. Use that API’s schema and business rules after checking syntax.
Why is a long number rejected?
JavaScript cannot represent every integer above 9,007,199,254,740,991 exactly. Quote identifiers such as order numbers to preserve every digit.
Will formatting preserve a signed request?
No. Whitespace, key order and number notation may change. Keep the original request if its exact bytes are used in a signature.