if you want to encode or decode an array from or to JSON you can use these functions
$myJSONString = json_encode($myArray);
$myArray = json_decode($myString);
json_encode will result in a JSON string, built from an (multi-dimensional) array. json_decode will result in an Array, built from a well formed JSON string
with json_decode you can take the results from the API and only output what you want, for example:
echo $myArray['payload']['ign'];