Sport coaching researchers have stressed the need for reflection in practitioners whilst the increased growth and impact of online applications has offered new ways to pursue this important goal. Recently, Stoszkowski, Hodgkinson and Collins (2021) showed that Flipgrid, an online communication tool that enables short video-based interactions, was a useful tool for facilitating and promoting analytical interaction between student-coaches on a bachelor's degree programme. The present study used realist evaluation to examine this successful use of Flipgrid. A range of methods including surveys, participant observation, content analysis of video transcripts and a semi-structured focus group interview were used to develop preliminary theories regarding how, when and why Flipgrid facilitated and promoted more analytical interaction than earlier studies using online written blogs. Individual realist interviews were then conducted to refine these theories, resulting in three main components: convenience, connection and criticality. This research provides a coherent and plausible explanatory account of the causal processes through which the use of Flipgrid in this specific circumstance produced its outcomes, which may be useful to those implementing reflective practice interventions in similar educational settings.