JSON Formatter

What is JSON Formatting

JSON (JavaScript Object Notation) is the most widely used data interchange format. API responses typically return minified single-line JSON that's difficult to read and debug. A JSON formatter converts compressed JSON into indented, human-readable format while validating syntax correctness.

Syntax Quick Reference

Type	Syntax	Notes
String	"value"	Double quotes only; supports \n \t \uXXXX
Number	42 / 3.14	NaN and Infinity not supported
Boolean	true / false	Must be lowercase
Null	null
Array	[1, "a", true]
Object	{"key": value}	Key must be double-quoted

Not supported: Comments, trailing commas. Integers larger than 2⁵³ lose precision — use strings instead.

Common Use Cases

• Debugging API responses: format single-line JSON into readable structure to quickly locate fields
• Editing config files: format package.json, tsconfig.json, etc. before making changes
• Data validation: instantly detect syntax errors like missing quotes or commas after pasting
• Documentation: embed formatted JSON as examples in technical docs

How to Use

1. Paste your JSON text into the input area, or click the "Example" button to load sample data
2. The tool automatically formats and syntax-highlights the output; errors are shown with their position
3. Choose your indentation (2/4 spaces or Tab), then click "Copy" to grab the formatted result

FAQ

Why am I getting "Unexpected token"?

Usually caused by single-quoted strings, trailing commas, or comments in your JSON. Standard JSON only supports double quotes and does not allow comments or trailing commas.

What about number precision loss?

JavaScript's Number type cannot accurately represent integers beyond 2⁵³ - 1. If your JSON contains large integers (e.g., snowflake IDs), convert them to strings at the source.

Does this support JSON5 or JSONC?

This tool strictly follows the RFC 8259 standard. If your data contains comments or trailing commas, you'll need to remove those non-standard extensions first.