What validation checks
The formatter uses the browser’s strict JSON parser. Property names and strings require double quotes; trailing commas and comments are not valid JSON.
Formatting versus minifying
Formatting adds indentation for readability. Minifying removes optional whitespace for compact storage or transfer. Both preserve the parsed data values and key order.
Example
The compact value {"active":true,"count":3} can be expanded into an indented object without changing its meaning.