Contextual information are used to describe situations of entities (users and devices) and their interactions. Applications need such information in order to adapt their behaviour in response to changes in the entities context. In certain scenarios and in particular machine to machine, the integration of a large number of components makes the management of the generated contextual information a very complex task. There absence of scalable and easily programmable solution for an efficient context management in complex and distributed environment is a show stopper. In this article, we propose a scalable cloud-based framework for context management able to handle contextual information in large distributed environments. This framework has been implemented and evaluated; it provides applications with a XML-based programming language to allow them customizing subscriptions to context changes and defining how context data.