JSON Formatter & Validator
Paste your JSON data to format and validate it instantly
📝 JSON Editor
About JSON Formatter
A JSON formatter takes minified or messy JSON and re-indents it so the structure is readable, while validating the syntax as you type. If the document is malformed, the tool reports the character position where parsing failed instead of silently returning nothing.
How validation works
The editor parses your input on every keystroke. Valid JSON is re-serialised with consistent indentation; invalid JSON stops at the first syntax error and reports where it happened. The most common causes are a trailing comma after the last item, single quotes instead of double quotes, and unquoted keys — none of which are legal JSON even though JavaScript accepts them.
{"a": 1, "b": 2,} fails, because JSON does not permit a comma before the closing brace. Removing it gives valid JSON: {"a": 1, "b": 2}Why does my JSON say “Unexpected token”?
That message means the parser found a character it cannot use at that point. Check for a trailing comma, a single quote where a double quote belongs, an unquoted key, or a stray character pasted from a terminal or a log file. Copying JSON out of a log often brings escaped quotes (\") with it, which must be unescaped first.
Is my data uploaded anywhere?
No. Parsing and formatting happen in your browser with JavaScript. Nothing is transmitted to a server, so it is safe to paste API responses that contain tokens or personal data.
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