This research is concerned with the use of development applications using mobile devices as a tool for blended learning models. However, in developing learning applications, one important concern is the user interface (UI). Therefore, the purpose of this research is to find out which UI design components are easy to use according to the user to be more user friendly, so that the purpose of using mobile applications for education can be realized. This study covers design principles that are appropriate for applications developed for platforms. Based on research, user interface testing has been carried out from 5 user interface principles and analysis using the System Usage Scale (SUS) given to 32 respondents. The results showed that the majority of respondents agreed that the mobile application developed had met the requirements of the user interface element. © 2021 IEEE.