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JSON Formatter & Validator
Paste JSON and get it indented, minified, or rejected with an explanation of what is wrong and where. Formatting happens live as you type.
How to use it
- Paste your JSON into the box — it is formatted automatically as you type.
- If it is not valid, the message under the buttons tells you why.
- Use Minify to strip all whitespace, and the indent selector to change the formatting style.
Why it stays private
JSON pasted into a formatter is very often an API response, which typically carries tokens, internal hostnames, customer records and identifiers. Because parsing happens in the page, none of that reaches a server.
Questions
Why does it say my JSON is invalid when it looks fine?
The most common causes are a trailing comma after the last item, single quotes instead of double quotes around keys and strings, unquoted keys, or a comment. Standard JSON allows none of those — even though JavaScript does.
What does minifying do?
It removes every character that is not required: indentation, line breaks and spaces between tokens. The data is identical, the file is smaller. It is useful when embedding JSON in a URL, a header, or a config value.
Can it handle large files?
Yes, within the limits of your browser's memory. Tens of megabytes are usually fine. Extremely large documents may make the tab slow, since formatting re-runs on every keystroke.