[gaptoothclan]

I was reading this and thought event based system for generating the billable quantities. I am sure billing by api call or data consumption must be done by an event driven system, if my customers are doing a billion requests a month, I probably do not want that data in my database. I would have also thought logging would be your friend in generating reports to reconcile your accounts. Some form of message cache to ensure it has not been processed twice would help.