mod_nibblebill is a credit/debit module for FreeSWITCH. The module was initially written by Darren Schreiber to fill the gaps of a professional grade trunking system that lacked the ability to detect fraud real-time. Its purpose is to allow real-time debiting of credit or cash from a database while calls are in progress. Darren had the following goals:
Debit credit/cash from accounts real-time
Allow for billing at different rates during a single call
Allow for warning callers when their balance is low (via audio, in-channel)
Allow for disconnecting or re-routing calls when balance is depleted
Allow billing functions listed above to operate with multiple concurrent calls