A method and system for interfacing between a caller application and a service module. A request for performing a transaction from the caller application is received. The request includes at least one caller application attribute describing the request. A service module data structure is built pursuant to the received request. The service module data structure includes a generic service document and at least one service module attribute. Each service module attribute is stored in a relational table of the service module data structure. The request is serviced within the service module data structure, which results in instantiating the generic service document. The generic service document is returned to the caller application.