In the modern world, IT technologies are widely used in the educational process at every level of learning. Various platforms, mobile apps and Internet services are successfully involved in language learning and have already become an integral part of it. In this research the functionality of the platform Quizlet is being investigated. Nowadays Quizlet is gaining popularity as an instrument of learning foreign languages worldwide, including Russia. Quizlet is an Internet service, which suggests students work with flashcards, prepared by a teacher, and different types of tasks, which are connected with the flashcards and should be completed in an entertaining, playful way. Many researchers consider this service as a way of vocabulary acquisition for students and insist on its high effectiveness in developing lexical skills and knowledge. Indeed, from this point of view Quizlet has many indisputable advantages. The users are able to get acquainted with written and oral form of a word, to affirm their knowledge in various types of activity and to see their progress instantly. Moreover, in combination with classwork and group study Quizlet can be a good way to attract students' attention by turning studying into interactive process. However, the platform Quizlet is also being extensively used for solving other problems of educational methodology, including the monitoring of students' knowledge with the help of tests and quizzes, which is extremely important in educational process. In this respect, the platform Quizlet has certain weak points, connected with the impossibility to use all the suggested options to complete various types of tasks or organizing the tasks in a right methodical way. The article is aimed to study the full functional potential of Quizlet and give recommendations on creating the Quizlet assignments which would be suitable for checking students' language skills and made up properly from methodological and technical point of view.