YurlieJSON Formatter
Format, validate, and minify JSON — all in your browser, no data sent to servers.
What does a JSON Formatter do?
A JSON Formatter (also called a JSON Beautifier or JSON Pretty Printer) takes compact or poorly-indented JSON and reformats it with consistent indentation, making it easy to read and navigate.
This tool also includes a JSON Validator that checks for syntax errors and a JSON Minifier that removes all unnecessary whitespace to produce the smallest possible output.
Common JSON errors
| Error | Example | Fix |
|---|---|---|
| Trailing comma | {"a":1,} | Remove the last comma |
| Single quotes | {'key':'value'} | Use double quotes: {"key":"value"} |
| Unquoted key | {key: "value"} | Quote the key: {"key":"value"} |
| Missing comma | {"a":1 "b":2} | Add comma: {"a":1,"b":2} |
| Undefined | {"a": undefined} | Use null instead of undefined |
Frequently Asked Questions
Is my JSON data sent to a server?
No. All JSON formatting, validation, and minification happens entirely in your browser using JavaScript. Your data never leaves your device.
What is the difference between formatting and minifying?
Formatting adds indentation and line breaks to make JSON human-readable. Minifying does the opposite — it removes all whitespace to reduce file size, which is ideal for production APIs and storage.
What is valid JSON?
Valid JSON must use double-quoted keys and string values, must not have trailing commas, and must use null (not undefined). Numbers, booleans (true/false), arrays, and objects are all valid JSON values.