This paper Proposes the individual roles for developing small web application systems based on the Client/Server architecture with the activities and artifacts of each role and cooperation. The roles of Web Server part (i.e. User Interface Designer, Web Designer, HTML Writer), the roles of Application Server part (i.e. Domain Expert, Application Developer, Tester) and the roles of DB Server part (i.e. Database Administrator, Data Designer) are described. Furthermore, the role of the Development Leader that participates in development and manages all works in project and finds the solutions of problems in project, is also discussed. The Domain Expert analyzes the domain of the application in order to send the artifacts to the Application Developer. Then the Application Developer analyzes, designs and implements the application based on the artifacts of the Domain Expert and integrates the implemented program modules. Roles are related each other in this way, and cooperate until the application development is completed. Finally, we analyzed and compared these roles with the roles of RUP(Rational Unified process) and web wave. Suggested roles in this paper turned out to be efficient compared to the roles of the existing large-scale methodology.