Format and beautify JSON, minify it, sort keys and validate it, with the exact line and column of any syntax error.
Pretty-printing adds indentation and line breaks so nested data is easy to read; minifying removes all whitespace to make it smaller.
Common errors the validator catches: trailing commas, single quotes instead of double, unquoted keys and comments, none of which JSON allows.
The most common causes are a trailing comma after the last item, single quotes, or a missing comma between items. The error message shows where.