mHealth apps are an effective means of delivering health interventions, and the college-age population is particularly proficient at using apps. Informed by current theories of Ecological Momentary Interventions (EMI), Motivational Interviewing (MI), and the Transtheoretical Model (TTM) of Change, investigators have developed a self-monitoring app-Reductions through Ecological Momentary/Motivational Intervention/Transtheoretical (REMIT)-with the aim of reducing hazardous drinking among college students. The app was developed using the Integrate, Design, Assess, and Share (IDEAS) framework. This step-by-step process for developing digital behavior change interventions was conducted in five phases to: (1) understand the users, (2) determine target behavior, (3) base the intervention in behavioral theory; (4) create delivery strategies, and (5) develop the REMIT prototype. REMIT uses assessments (informed by EMI) and components of MI and TTM to guide administration of nine modules designed to engage users in reducing alcohol use and related problems. REMIT users self-monitor their alcohol consumption and develop strategies to change drinking behaviors using a range of easy-to-use features, such as the Virtual Coach, automated text messages, interactive gaming mechanisms (gamification), drink consumption tracking, and Blood Alcohol Concentration (BAC) calculators. mHealth interventions have been shown to reduce alcohol use among college students when they are applied in real-life, real-time contexts. REMIT is a theory-based app that incorporates user-friendly features to reduce hazardous drinking among college students. The next step is to conduct a pilot trial to test the efficacy of the app and enhance the REMIT prototype.