With the rapid cloud computing growth, the way we use technologies is changing and at the same time it offers a great possibility to develop new modern services. The purpose of the diploma thesis is to research the possibility of developing applications in this area. The thesis describes the development of business applications on the Force.com platform. Integration between different platforms, which is the primary task of application, requires wide knowledge of modern technologies. We are going to evaluate the relation to the Force.com platform. The main part of the developed application is Java powered, hosting by Heroku platform. Later on we briefly describe cloudy concepts such as SaaS, PaaS and IaaS. Specifically we describe the CRM system, as it is the center of our application, which associates CRM with focused system for e-mail marketing. In addition to the technical solution, we describe the steps for publishing application to the AppExchange marketplace.