The Oasis app is a self-appraisal tool for potential or current problem gamblers to take control of their habits by providing periodic check-in notifications during a gambling session and allowing users to see their progress over time. Oasis is backed by substantial background research surrounding addiction intervention methods, especially in the field of self-appraisal messaging, and applies this messaging in a familiar mobile notification form that can effectively change user’s behavior. User feedback was collected and used to improve the app, and the results show a promising tool that could help those who need it in the future.