Format JSON without uploading it
The formatter parses JSON in the page. Invalid input stops at the parser error, and the text never becomes an API request.
The JSON formatter and the minifier both call the browser's JSON parser.
That means trailing commas, comments, and single quotes fail, because they are not JSON. The error text is the parser's message. Fix the document locally and format it again.
Pretty output uses an indent from 0 to 8 spaces. Minify writes the same value with no insignificant whitespace. Neither tool gzips the result, and neither sends the document to DevKitNow.
Clear the tool or leave the page when you are done. The document is not saved.