This app is very simple, you have a multiline editor with variables were you can write your own JSON-code and add values from variables. For example you can pickup an XML file in Switch and make a JSON file out of it.
Please be aware that there are three versions of this App. Make JSON v.1 is for Switch 17.1 and lower and Make JSON v.2 and v.3 is for Switch 17.2 and higher. Please install accordingly.