Techniques and architectures for customizable modular line item evaluation

Pluggable pricing modules with functional extension points. A plurality of pricing methods are installed with a pricing service. The pricing service has a pluggable architecture to accept pricing methods including a set of pricing functions, and one or more extension points that provide programmatic hooks within an operational flow of the pricing service to provide optional interfaces to functional modules external to the pricing service. In response to a pricing request for a sales transaction, the pricing request including a pricing resolving selected pricing method for each sales item of the one or more sales items from the plurality of pricing methods. At least one of the one or more extension points are used to call an external functional module to interact with the operational flow of the pricing service. Aggregated results are provided to the source of the pricing request.