The moment we decided to put the idea of this application into practice and bring it to life, we accepted some new challenges that were different from the ones we had encountered before. One of them was application design. Given the circumstances at the time of application development, we had to design it ourselves. We set the time aside time and managed to go from a somewhat vague idea to observing how application design develops within a few days. Considering that we wanted the applications to be published as soon as possible, we decided to develop the client app using native technologies, and the admin one using cross-platform technology. A new challenge was set. During the development of these applications, we were given the opportunity to implement several interesting functionalities, such as working with a QR code generator and scanner, displaying user activities by days and months, and filtering data. The main idea of the app is to facilitate the repetitive process of checking and registering users in fitness centers, to enable the aggregation and storage of all information about users, and, if necessary, to enable their quick and easy download. Thanks to the cooperation with partners from the Addiction Fitness Center from Novi Sad we got an insight into how the process functions in practice, so we directed the development of applications accordingly.