Rescuing and Rebuilding a Health Research Platform into a Stable, Scalable Mobile Experience
the challenge
The PrEPsmart app supports participants in medical studies tracking their usage of 2+1+1 on-demand PrEP (pre-exposure prophylaxis) to prevent HIV infection. The app features advanced logic-based dosing reminders, pill tracking, sexual activity logging, protection status updates, and SMS notifications—all within a secure and user-friendly mobile interface. Before working with us, Heluna Health and the San Francisco Department of Public Health had gone through five different development teams trying to stabilize the product and prepare it for study deployment. Every partner fell short—delivering unreliable, buggy, or incomplete builds that could not meet the standards required for clinical research.
the solution
Mountain Dev stepped in to do what others couldn’t: stabilize and deliver a reliable app for live research use.
We conducted a full codebase salvage and architectural audit, rebuilding the app’s critical logic layers, notification engine, and dosing tracking features to meet the complex requirements of the randomized controlled trial (RCT) led by UCSF and the SF Department of Public Health.
We worked directly with the product owner and study team to execute detailed QA passes and implement time-based and behavior-based triggers. The final result is a robust, cross-platform mobile app that balances a clean user interface with highly specific study protocols and logic trees .
the results
Our engagement with PrEPsmart didn’t stop at technical execution—we also helped navigate a complex and high-stakes regulatory process.
Because PrEPsmart is tied to a medical study involving personal health data and behavioral tracking, both Apple and Google flagged the app multiple times, delaying its release. Each rejection cited sensitive health-related functionality, participant risk, and requirements around privacy disclosures and data handling.
We partnered closely with the client, legal team, and the reviewers at Apple and Google to respond line-by-line to compliance issues, eventually securing full approval and successful listing in both app stores. This was not a one-time fix—it required multiple submission rounds, precise technical adjustments, and strategic messaging around privacy, user consent, and institutional oversight. In addition to clearing the regulatory hurdles, we delivered:
A fully rebuilt, study-ready mobile app that supports a randomized controlled trial funded by the National Institute of Mental Health.Reliable, logic-driven reminders and protection status indicators that match the complex rules of on-demand PrEP dosing (2+1+1).Integrated support for SMS reminders, passcode protection, multilingual onboarding, and privacy-first logging of sensitive data.Ongoing QA and maintenance support, ensuring the app remains compliant and functional across new OS versions and device types.