Mouseover the JSON key to see a brief description of each key. Keys that either haven't been identified (or that we haven't gotten around to adding yet) will show 'XXX'. Keys that are light gray are obsolete/legacy but still are returned in API responses.
If you're creating tasks programatically don't confuse 'employee_id' with 'employees'. 'employees' is an array of objects and 'employee_id seems to be a hold-over from some previous incarnation of task assignment.
If you spot a mistake or know the purpose of an undescribed key please let us know by emailing kickservapi@veildg.com.