To respond to the growing needs of evolution and adaptation coming from the modern open connected world, applications must continuously monitor their own execution and the surrounding context. The events to be observed, belonging to guaranteed functional and non-functional properties, can themselves vary in scope and along time. Therefore the monitor must be easily con figurable and able to serve differing event consumers. To address these requirements, we developed the Glimpse monitoring infrastructure conceived having flexibility and generality as main concerns. The paper introduces the architecture of Glimpse and shows how it can support runtime performance analysis through a simple example.