This study is designed to adapt and evaluate an innovative, engaging mHealth intervention to prevent young opioid users (18-29) from transitioning to injection drug users (IDU). This intervention has the potential to have tremendous impact on improving access, acceptability, and potency of opioid use interventions for youth. Given the extremely widespread use of mobile apps among young adults, evidence-based mHealth interventions could have significant reach for this difficult-to-engage population.