The JSON data is an object (basically an associative array). Indexed arrays use square brackets, [0,1,2], while associative arrays use curly braces, {x:1,y:2,z:3}. Any of the data within the outermost object can be either type of array, but the outermost object itself has to use curly braces.
https://stackoverflow.com/questions/11197818/how-do-i-make-a-json-object-with-multiple-arrays

