Students’ engagement is widely believed to be the single most significant predictor of persistence in learning process. It is generally reflected in active participation such as listening to presentation, expressing opinions, asking questions, and working on assignment. However, the idea of being embarrassed in front of peers and the feeling of being reluctant to disturb others can often be intimidating for many students and might prevent them to ask questions during class discussion. As the consequence, meaningful discussion that is expected to happen during the lesson oftentimes takes another form of side conversation such as whispering, note passing, and text messaging, the so-called backchanneling. In addition to this, the class size has also been generating another problem. The larger the class is, the greater challenges the teachers face to engage students in their learning. To address this issue, this research investigates how TodaysMeet, a digital backchannel chat platform, promotes students engagement in an Indonesian EFL large class and transfers the side conversation to the forefront. A number of 41 college students took part in this single-case study approach. The research data were taken from interviews, classroom observations, and students' task submission. The degree of students’ engagement was measured in 3 types of engagement i.e. emotional, behavioral and cognitive engagement. Research findings suggest that the digital backchannel promotes students engagement with learning activity, and enables lecturers to provide immediate feedback on the students understanding over the lesson material.