The HealthMindr study is a randomized-controlled trial of a mobile app, HealthMindr, to assess whether access to the app will increase uptake of PrEP among MSM in the Southern United States. The app features PrEP-specific resources including general information, FAQs, and a PrEP provider locator. The app also includes HIV/STI information, HIV and STI home test ordering, condom and lube ordering, the ability to create HIV/STI test plans, HIV/STI testing locators, as well as self-assessments for PrEP, PEP, and substance use and mental health. The study will enroll over 650 MSM in Atlanta, GA; Jackson, MS; and Washington, DC. Participants will either receive access to the HealthMindr app or to standard of care HIV prevention information, and PrEP uptake will be measured over a 12-month period. The HealthMindr study is funded by the National Institute on Drug Abuse of the NIH.