The objective of REFLECT2D (Real-time Engagement For Learning to Effectively Control Type 2 Diabetes) is to evaluate whether pairing real-time glycemic and health behavior data leads to improved glycemic control among adolescents and young adults with type 2 diabetes. Participants will use a mobile app that integrates continuous glucose monitor data, Fitbit activity tracker data, and diet logging, with the aim of increasing capability to interpret glycemic data (including impacts of physical activity and dietary intake), providing opportunity to plan and implement behavior change, and increasing motivation to engage in health behaviors. After an initial educational session and run-in period, a 90-day micro-randomized trial (MRT) period will involve once daily randomization of each participant to: 1) physical-activity focused prompt, 2) dietary intake-focused prompt, or 3) no prompt. After the MRT, a 90-day observation period without prompts but with ongoing availability of continuous glucose monitor data, Fitbit, and Healthmine app will examine persistence of glycemic and behavior changes.