Online tutors play a critical role in e-learning and need to have an appropriate set of skills in addition to subject matter expertise. This paper explores how digital badges can be used to encourage the development of online tutoring skills. Based on previous research, we defined three digital badges, which are examples of essential tutoring skills. These skills were self-assessed during two weeks by online tutors in K-12 mathematics, who also wrote a self-reflection based on their experience. The digital badges motivated tutors to reflect on online tutoring practices. The tutors described that they gained a more detailed understanding of the tutoring process when continuously analyzing ongoing conversations. However, it was a challenge for the tutors to balance the private activity, reflection on tutoring skills, and the social activity, communication with the K-12 students. It is essential to take into account when tutors will have time to reflect, for example, by scheduling time for reflection or enabling opportunities for reflection that is flexible in time. A challenge for further research is to better understand the potential benefits of different types of badges.