JSON Validator
Check JSON syntax and find errors quickly.
Developer Tools
JSON Formatter
Make your JSON clean, readable, and easy to debug.
JSON Formatter
Powered by UtilBrixHow to use this tool
- Paste a complete JSON value into the input field.
- Choose Format and an indentation style, or choose Minify for compact output.
- Run the tool; fix any syntax error before copying the result.
- Review large identifiers and duplicate object keys before replacing the original data.
Formula & method
JSON is parsed with the standard JSON parser, then serialized with two spaces, four spaces, tabs, or no added whitespace. Parsing rejects trailing commas, comments, and unquoted object keys. Very large numeric literals may lose precision under JavaScript number semantics.
A practical example
The input {"a":1,"b":[2,3]} can be expanded into an indented object, or compacted back into one line without changing its JSON structure.
When this tool is useful
Inspect nested API responses, make configuration files easier to review, or create a compact JSON payload. Formatting changes presentation, while validation checks syntax; neither confirms that an API accepts the document structure.
Common mistakes and limitations
- JavaScript numbers can lose integer precision beyond the safe integer range; represent exact large identifiers as strings.
- Parsing and serializing can collapse duplicate object keys. Preserve the original input when investigating malformed producer output.
Frequently asked questions
Why are comments or trailing commas rejected?
They are not part of standard JSON syntax. Remove them or use the parser for the format you actually have, such as JSONC or a JavaScript object literal.
Does formatting validate my API schema?
No. A syntactically valid document can still omit required fields or contain incorrect types. Check the API schema separately.