In our current connected wireless world, mobile devices are enabled to use various networking facilities. Although this enables mobile users to communicate any time and any place, it may also be very intrusive. There is a high need to manage the information stream a user receives on his/her mobile device. Context-awareness seems to be a promising way to manage this information stream and to provide the means to communicate at the right time in the right way. Current context-aware applications benefit from the user context (e.g. location information), however, they do not consider the quality of service (QoS) offered by various networks (i.e. only best-effort QoS is considered). The research discussed in this paper focuses on a QoS- and context-aware service infrastructure supporting the development of mobile applications in a heterogeneous network environment. We argue that the use of context information helps to better capture the user's required QoS and improves the delivered QoS.