This paper demonstrates practical applications based on SAGA–A Simple API for Grid Applications–for distributed computing resources over multi-middleware infrastructures. SAGA provides a high-level programming interface that bridges between applications and Grids as well as local schedulers such as PBS. At the Computing Research Center of KEK, we are playing a role to support not only on-site users, but also domestic university groups in the High Energy and Nuclear Physics (HENP) community. In order to provide a more effective and practical client environment to users, we have developed Grid-adaptive applications based on SAGA as a part of activity in the RE sources li NK age for E -sc I ence (RENKEI) for the general purpose e-Infrastructure using National Research Grid Initiative (NAREGI) middleware. We present the technical details for the user environment demonstrator and discuss the usability by real HENP applications.