Developing Science Gateways at Various Levels of Granularity Using WS-PGRADE/gUSE

Science gateways can provide access to distributed computing resources and applications at very different levels of granularity. Some gateways do not even hide the details of the underlying infrastructure, while on the other end some provide completely customized high-level interfaces to end-users. In this chapter the different granularity levels at which science gateways can be developed with WS-PGRADE/gUSE are analysed. The differences between these various granu-larity levels are also illustrated via the example of a molecular docking gateway and its four different implementations.