Free online tools
JSON formatter and validator
Paste JSON and the tool checks it, formats it or minifies it. If something is wrong it points to the line and column.
Your data never leaves your browser. Nothing is sent to a server.
How to use it
- Paste or type JSON into the input field.
- Choose two-space or four-space indentation, or minify.
- If the JSON is invalid, read the message with the line and column.
- Copy or download the result.
Common JSON mistakes
Typical problems are a trailing comma after the last item, single quotes instead of double quotes, unquoted keys, comments and missing brackets. JSON is stricter than JavaScript object literals.
Formatting vs minifying
Formatting adds indentation and line breaks so it can be read. Minifying removes unnecessary whitespace, which shrinks the payload sent over an API. Structure and values stay unchanged.
Data privacy
Parsing happens in your browser. You can safely check API responses and config files, including ones with data that must not be sent to external services.
Frequently asked questions
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