Tylko Jeden is a free mobile application developed by Cyfrowy Polsat S.A. for Android users. It is a companion app for the reality show program of the same name, which features 10 MMA fighters competing for a contract with KSW - the largest MMA federation in Europe. The program consists of 8 episodes, each of which concludes with a fight that determines which participant will continue training and who will be eliminated from the show. The app allows users to follow the fighters' journey through additional materials published chronologically to the broadcast episodes. Users can also learn more about the elements of training, diet, preparation for fighting, losing weight, and other aspects of MMA through the app. Additionally, the app features quizzes and surveys related to the participants and the entire MMA discipline.