An electronic pharmacy adjudication system and associated method and computer program product for performing adjudication service for a healthcare insurance claim is provided. The system includes an interface layer, an orchestration layer and a service and rules engine layer configured for receiving, processing and releasing an adjudication decision. The orchestration layer processes the healthcare insurance claim to generate a sequence of service calls to the service and rules engine layer to derive a sequence of partial decision results, which are derived by processing a set of parameters identified by the service call according to a corresponding subset of decisions rules in a rules repository. The sequence of partial decision results is then processed to derive the adjudication decision corresponding to the healthcare insurance claim.