Understand the result
A response that stays exact
{"order_id":"9007199254740993","items":[{"quantity":2}],"paid":false}The order ID is a string so the digits remain exact. Formatting changes presentation, not the application meaning of the fields. A syntax-valid response can still violate your API contract.
Fix one error at a time
Start with a synthetic copy, choose Validate and fix the first reported error. A trailing comma before a closing bracket is invalid JSON. After validation, choose Format for readable indentation or Minify for a compact representation.
What this tool can and cannot tell you
Formatting helps review API responses. Validation checks syntax, not an API schema. Unquoted unsafe integers, overflow and nonzero underflow are rejected; quote exact identifiers. Decimal fractions still use binary floating point. Duplicate object names retain their last value.
Common questions
Does valid JSON mean my API request is correct?
No. A syntactically valid value can have missing fields, wrong types or values your API rejects. Validate against the API contract separately.
Why do I get a trailing-comma error?
Remove the comma directly before the closing } or ]. Keep commas between adjacent members or array values.
Does this tool upload my JSON?
The product workspace parses JSON in an isolated browser frame. Anonymous action names are measured by the parent page; the payload itself is not included in those events.
Worked examples are synthetic. No customer outcome or saving is implied. Content by Orr Yoffe.