JSON Formatter
Format, validate, minify, and analyze JSON — 100% client-side.
What is a JSON Formatter?
A JSON formatter (also known as a JSON beautifier or JSON pretty printer) takes raw or minified JSON text and reformats it with consistent indentation, line breaks, and spacing to make it human-readable. This is essential when working with API responses, configuration files, log data, or any JSON that has been minified for production.
Common JSON Errors and How to Fix Them
Unexpected token
Cause: Usually a missing comma between key-value pairs or array elements.
Fix: Add a comma after each element except the last one.
Trailing comma
Cause: A comma after the last item in an array or object.
Fix: Remove the trailing comma. JSON does not allow trailing commas (unlike JavaScript).
Unclosed string
Cause: A string value missing its closing quotation mark.
Fix: Add a closing double quote at the end of the string.
Invalid escape sequence
Cause: A backslash followed by an unsupported character.
Fix: Use valid escape sequences: \", \\, \/, \b, \f, \n, \r, \t, or \uXXXX.
Frequently Asked Questions
Is my JSON data sent to a server?
No. All formatting, validation, and analysis happens entirely in your browser using JavaScript. Your JSON data never leaves your device.
What JSON errors can this tool detect?
This tool detects invalid syntax, unexpected tokens, unclosed strings and brackets, trailing commas, duplicate keys, double-encoded JSON, and deep nesting warnings.
What does Sort Keys do?
Sort Keys alphabetically reorders all object keys at every nesting level. This makes large JSON files easier to diff and compare between versions.
What does Minify do?
Minify removes all whitespace and newlines from JSON, reducing file size. This is useful for API responses and production configurations where readability is not needed.