Reactive sever technologies getting increasingly popular. They are characterized by relying on asynchronous, non-blocking functions and, in that way, are significantly more efficient than classical thread-based techniques. Two technologies for the Java platform are Ktor and String Boot. Ktor is a server programming platform for the Kotlin programming language. Sprint is a comprehensive platform for the Java VM which already has a long development history and a huge user group. Both offer various asynchronous programming features. In this project, the two technologies should be compared based on a typical server application.