In recent years the use of smartphones has increased because the convergence of technologies related in the development of these mobile devices. This convergence relates to communication, handheld devices and applications. The most common development platforms are Android, iOS, Windows Phone and Symbian. In most cases mobile application developers restrict the development to one or two platforms, since there is not strong multi-platform execution support. For example, an iOS application will not run on Android or another system. One solution is web development, but it presents some problems such as adaptability, overload on servers, low use of device capabilities, and poor code reuse. A better solution is to develop a middleware that helps to develop open applications. This paper gives an analysis of the problems involved in the design of open mobile applications, challenges and some solutions.