JSON Formatter

No. Everything runs in your browser with your own JavaScript engine. Open the Network tab while you format and you’ll see no request carries your JSON. It never leaves your device — safe for tokens, API keys or customer data.

We report the exact line and column of the first character the parser can’t accept. One caveat true of every JSON parser: a missing comma is often detected on the next line, so if the error points at a } or a property name, check the line above — the tool reminds you of this.

No. We parse your JSON and re-serialise it, so the values are identical — only whitespace (and key order, if you turn on Sort keys) changes. Parsing the formatted output gives back exactly the same data structure.

JavaScript — like the JSON standard in most languages — stores numbers as 64-bit floats, so an integer larger than 9,007,199,254,740,991 loses precision on parse. That’s a platform limitation, not something this tool can avoid; if you need big integers, keep them as strings.

No — strict JSON forbids both, and so do we. If your input has them, Validate will point to the offending character so you can remove it.

Nothing. It alphabetises the keys inside objects but never reorders array elements, because reordering an array would change your data’s meaning.