Y-TOP is the official mobile app of Yonsei University, designed for both students and faculty members. The app offers a range of services, including a connection to the university's mobile web services such as the homepage, academic portal, YSCEC, and library homepage. It also provides integrated app services such as a mobile ID, electronic attendance, library seat reservation, and shuttle bus schedules.

One of the unique features of Y-TOP is the Y-DIARY (calendar), which allows users to view and keep track of campus events, including cultural, artistic, and academic activities, in addition to announcements and real-time alerts. The app also offers a weekly menu service that displays the cafeteria's menu and the degree of congestion.