JSON Formatter / Minify / Validator

Format adds 2-space indentation for readability, while Minify strips all unnecessary whitespace and line breaks to shrink the file size. Both modes only reformat the structure — the actual characters inside string values are never touched.

Yes — formatting, minifying, and validation all happen entirely in your browser via JavaScript. Nothing is uploaded to any server.

The most common cause is a trailing comma before a closing bracket or brace. Some programming languages allow that, but the JSON standard does not, so the parser reports an error right at that spot.