Limitations
The results of this study should be viewed in the context of the limitations. First, this pilot study included a small sample size and short-term follow-up (ie, 30-days) and used a single-arm design that is commonly used in beta testing; therefore, it was not powered or designed to evaluate efficacy. Second, our participants were subject to selection bias across several dimensions. For example, we recruited men using Facebook or a dating app (ie, Hornet) who may have been more comfortable using mobile apps than other men (ie, hidden MSM). Moreover, participants were already engaged, at least in part, due to their prior high levels of HIV testing. Participants were enrolled in the Greater Kuala Lumpur area only, potentially limiting the generalizability of the findings. Third, social desirability bias may have led participants to speak more positively about their app experience during the survey and exit interviews. This was in part observed by participants who responded favorably to app features, but our usability testing had not confirmed they used the specific feature. Finally, HIVST kits and PrEP services were free to the participants, which may have led to an overestimation of the actual uptake of HIV testing and PrEP services.