In our study we exploit digital tools in order to foster a relational approach to mathematics undergraduate students. Specifically, we designed formative assessment workshops based on peer feedback, with the aim to promote self-assessment and reflection on one's own mathematical activity. In the paper we describe the design of an educational activity and investigate how the students perceived their experience with the designed formative assessment workshops. Furthermore, we provide evidence of the effectiveness of the designed workshops in terms of aligning students' feedback with the teacher's criteria.