The master's thesis presents the development of a web application for the Red Cross and a startup business plan. The application is primarily intended for the users of the Red Cross in Vrbovec, as well as for the employees and volunteers involved in the organization. The introductory section describes the issues, briefly introduces the work of the Red Cross, and outlines the content by chapters. In general, the thesis can be divided into two parts - the theoretical business section and the practical section. As the term itself suggests, the business part of the master's thesis describes the challenges that a product or company encounters when entering the market. An analysis of potential users, competition, as well as financial and marketing plans are included. In the practical part, the functionalities of the application are presented, and the development steps of the application are described. Finally, a conclusion is presented, analyzing the overall process of creating the thesis and proposing ideas for product improvement.