The invention relates to a software development kit and a terminal apparatus. A software development kit (SDK) that includes a Web service interface includes a communication unit, a conversion table, a reverse conversion unit and a conversion unit. The communication unit transmits a request message to a Web service and receives a response message from the Web service. The conversion table stores a pre-conversion side service method name of the Web service that is corresponded with a post-conversion side service method name. The reverse conversion unit, when data regarding the request message includes the post-conversion side service method name stored in the conversion table, converts the post-conversion side service method name into the corresponding pre-conversion side service method name. The conversion unit, when data regarding the response message includes the pre-conversion side service method name stored in the conversion table, converts the pre-conversion side service method name into the corresponding post-conversion side service method name. Therefore, smoother development of an extended application that utilizes Web services provided by a plurality of Web service providers can be provided.