Supporting Treatment Adherence for Resilience and Thriving (START)

1. Assigned male at birth; 2. Identifies as male; 3. Age 18 or older; 4. Reads and speaks English; 5. Continental US residency; 6. Reports ever having had anal sex with a man; 7. Self-reported HIV diagnosis for 3 or more months and currently taking anti-retroviral therapy (ART) 8. Reports a detectable viral load during past year OR no viral load test in the past 10+ months OR reports \< 90% adherence to ART; 9. Screens positive for a moderate or severe stimulant use disorder in the past 3 months with an abbreviated version of the National Institute on Drug Abuse (NIDA)-modified Alcohol, Smoking and Substance. Involvement Screening Test (ASSIST); 10. Has an iPhone or Android smartphone; 11. Is willing to participate in an mHealth intervention Exclusion Criteria: 1. HIV-negative or never tested for HIV; 2. HIV-positive men without a current ART prescription; 3. Does not return a viable DBS specimen at baseline for viral load testing 4. Not a sexual minority man