Mobile phones have become an essential part of modern family life. Their proliferation has been accompanied by a diverse range of apps, including apps for separated parents. Family law professionals are increasingly being asked about post-separation parenting apps by clients. Yet the empirical evidence about their potential benefits and risks is sparse. The present study draws on qualitative data from an online survey of 344 family law professionals in Australia and New Zealand about their attitudes to co-parenting apps. Three broad potential benefits of co-parenting app functions were identified: accountability, convenience and containment. Drawing on a realist evaluation framework, we find that the same app functions were identified as posing a variety of potential risks, including technology-facilitated abuse, depending on context. We argue that family law professionals need a good understanding of the potential benefits and risks of co-parenting apps, along with the contextual factors that can determine outcomes.