The purpose of pervasive applications is to be invisible and to require a minimal amount of user attention. But invisibility raises lots of hard challenges, blocking the long-awaited pervasive era to emerge. The device heterogeneity and volatility, security enforcement and context-awareness are just some of the issues a developer must tackle inside the application code. To industrialize such development, we propose to use an application server dedicated to the pervasive environment. Thanks to this server, developers focus on the application, delegating to the server most of the pervasive constraint management. However, providing such a platform is a very difficult task. The pervasive environment constraints must be handled by this server in a consistent way, while being flexible enough to support the different applications. This paper describes the requirements of the pervasive applications and how our platform, named iCASA, deals with them.