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JSON Formatter & Validator

Format, minify and validate JSON directly in your browser.

Input
Output

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Format and validate JSON

HandyKitz makes JSON easier to read by formatting it with consistent indentation. You can also validate JSON for syntax errors or minify it to reduce unnecessary whitespace.

Is my JSON uploaded?

No. JSON processing happens directly inside your browser. Your data is not sent to the HandyKitz server.

What is JSON minification?

Minification removes unnecessary spaces and line breaks while preserving the JSON data. This produces a more compact string.

Practical example

Formatting adds indentation; minification removes unnecessary whitespace. Neither operation is intended to change the meaning of valid JSON data.

Paste {"name":"Ada","active":true} and format it to put properties on indented lines. A trailing comma after true is invalid JSON and must be removed.

Frequently asked questions

What happens to duplicate object keys?

JSON.parse keeps the last value for a repeated key. For example, {"a":1,"a":2} becomes {"a":2}; formatting is not a duplicate-key audit.

How can I preserve a very large identifier?

Put it in a quoted string rather than a JSON number. JavaScript can round integers above 9007199254740991 during parsing.

Why are comments or trailing commas rejected?

They are not part of standard JSON syntax. Remove them from configuration-style input before using this formatter.

Why does the input null produce no output?

The current implementation uses null as its parse-failure sentinel, so standalone null produces no formatted output. Null values inside objects or arrays can be processed.