Abstract: According to an example embodiment, a non-transitory computer-readable storage medium may include instructions stored thereon that, when executed by a processor, result in a computing system receiving an event stream. The event stream may include event messages that document events occurring in relation to items being handled by an item handling service provider, and each of the event messages may be associated with instructions from a customer of the item handling service provider. The execution of the instructions may also result in the computing system classifying the event messages as events based on classification rules associated with the respective customers of the service provider. The execution of the instructions may also result in the computing system determining an aggregated fee associated with a subset of the events based on pricing rules associated with the respective customers of the service provider.