The length of time before your application's perodic usage counter restarts for this call. If the number of calls you make exceeds the periodic hard limit before the current period ends, further calls will be refused until the next period starts. Possible values: -1 (Periodic limit not enforced, could be any negative integer), 0 (Calendar month), 30 (Number of days, could be any positive integer). If the period is based on the calendar month, the usage counters restart on the same day of every month, regardless of the number of days in the month.
See the
Field Index to learn which calls use Period.