Introduction. This study is underpinned by two parallel trends. On the one hand, there is active engagement with the cultures of different countries and a desire to improve English proficiency. On the other hand, there is a discrepancy between the initial requirements for learning outcomes in the 'foreign language' (FL) subject and the actual learning outcomes achieved. One of the reasons for that is the heterogeneous level group. The research aims to assess the effectiveness of the Duolingo app in bridging the gap between levels within a group by setting a time limit for using the app. The continuous upgrade of the app also contributes to the study of its effectiveness. Materials and methods. The experiment took two semesters of one academic year and employed 46 first-year students, all of them showing levels from А1 to В2 (CEFR) on a placement test. The results showed that the level gap could not be bridged, but the students partially improved their writing and listening skills, and also began to feel more relaxed and familiar in a foreign language classroom because of the daily practice in the application. However, less than half of the students demonstrated a stable habit of using the application further due to the lack of real motivation. Conclusion. Despite the insignificant positive results of the study in relation to the stated aim, the application can be successfully used for sharpening syntactic structures, practicing listening and pronunciation, memorizing conversational cliches and vocabulary, using the spaced repetition method, for beginners.