The article is devoted to description of the CyberArenaPro system for holding cyber competitions that provides convenience and ease of organizing competitions of various levels, allowing to hold competitions on the online venues around the world, increasing opportunities for participation in the competitions via the Internet and mobile devices. The program is designed to automate holding cybersport competitions of various levels (from local to international) and of any disciplines and formats. The system has a service-oriented architecture and uses the object-oriented Redis database. For a client implementation, the concept of Rich Internet Application, the ReactJS platform and the JavaSc programming language are applied. The server and the client applications are integrated with the API means. The automated system was tested during the organization of competitions in the computer club «CyberArena». Competitions were carried out in accordance with the discipline CS:GO, and 64 teams participated. The «CyberArenaPro» system can be used to organize competitions of any kind of sport.