Championed by ideas of open source and transparency, coding for the “greater good” resonates with a wide variety of technologists, designers and developers. One of these issues is “mental health”: Having moved away from seemingly dusty therapist couches, mental health is now being “hacked” with modern technologies and sleek apps. However, designing and developing for a sensitive and distressing area is highly contextual and tricky to get “right”, potentially even dangerous. Using the design and development of a self-care app, this talk will offer examples on how a project can go wrong even when its maintainers mean well — and how to mitigate some of these fundamental risks and issues. Ideas of participatory design, societal stigma and community trust will be explored.