Aim 1: To determine the feasibility, acceptability, and usability of PL, the investigators will conduct mixed methods research among the DC Cohort Executive Committee members (one focus group with a maximum of 20 members), providers from each of the DC Cohort participating clinics (individual in-depth interviews with a maximum of 28 providers), members of the DC Regional Planning Commission on Health and HIV (COHAH; one focus group with a maximum of 50 members), and PLWH who receiving care at each of the DC Cohort participating clinics (four focus groups with a maximum of 8 clinic patients in each group for a total of 32; user testing sessions followed by a survey with a maximum of 14 clinic patients; and beta testing preceded by a short demographic survey and followed by a brief in-depth interview and survey with a maximum of 14 clinic patients). Following user testing, the research and developer teams will review formative results and finalize the optimal set of app features for this urban cohort of PLWH. Following beta testing, the research and developer team will review results and make final app modifications. The prototype will pass stringent testing showing the app to be 100% bug-free, with no data loss. The app has robust transmission retries and data caching on the phone during periods of internet signal loss. Once connection is restored, all cached events are automatically sent to the PL servers on AWS (Amazon Web Services) S3 and are synchronized. The investigators will proceed to beta testing when it passes data reliability testing (retry, cache, re-send) at a 0% failure rate.

For the focus group, interview, and user testing participants, consent will be obtained verbally and a waiver of documentation of consent is requested. For beta-testing participants, written informed consent will be obtained. For the EC focus group, COHAH focus group, and provider interviews, participants will be sent a link to a brief REDCap survey prior to the study activities. The surveys will not be linked to their identities. For the focus groups with PLWH, participants will also be sent a link to a brief REDCap survey prior to the focus groups. During the user testing sessions, participants will be asked to download the app onto their phones. Users will be shown various app features by the study team and asked to share their impressions. Following the sessions, testers will be provided a link to the REDCap user testing survey. Users will be assigned a unique survey ID that will be linked to their DC Cohort ID so that they can be compensated. During the beta testing, participants will be asked to attend a virtual training session where participants will download the PositiveLinks app onto their personal smartphone, a study team member will set up the participants' PositiveLinks app account, and a study team member will demonstrate how to access PositiveLinks and its features.

Throughout the beta testing period, the study team will continuously collect data paradata or data related to app usage. This includes the frequency with which each participant uses app features as well as in-app data such as content information from check-in entries and comments, reminders, and community message board comments. Data collection will also include a 15-minute virtual user interview to debrief usage, likes and dislikes, identify bugs, and provide recommendations after one month of PL use. Along with an interview, participants will also complete a quick survey that will question participants overall experience with the app.

Aim 2: Aim 2 will entail a Cluster Randomized Clinical Trial that randomizes DC Cohort clinic patients (n=482) to either PL (n=6 clinics), or to the usual care conditions for engaging and retaining people in HIV care (n=6 clinics). Participants will be persons living with HIV who are previously enrolled in the DC Cohort or are eligible to enroll in the DC Cohort and have factors that may put them at risk for poor retention in care or lack of viral suppression (e.g. not virally suppressed, not retained in care, gap in care \>=6 months, newly diagnosed, etc.). Participants from clinics randomized to PL will get the patient smartphone app; clinic staff will receive the provider portal and provider smartphone app, the provider online LMS (learning management system), and the RA (research associate) will use the administrative website to enroll participants. Patients randomized to PL will use it for 12 months or more; they can opt to use it as long as it is available during the study (access depending on enrollment date). Participants from clinics randomized to Usual Care: Participants from clinics randomized to Usual Care will receive usual clinic retention and medication adherence support services for 12 months . The usual care condition ranges from having no ancillary support to only case management, to Ryan White funding and comprehensive services (adherence support, patient navigation, mental health, substance abuse, dental services and food banks).Participants will be assessed at baseline, 6 months, and 12 months to measure the primary outcomes of a) viral suppression (i.e., VL\<200 copies/ml) at 12 months, b) Visit Constancy (i.e., proportion of 4-month time intervals in which 1 HIV care visit was completed in 1 year, and c) Retention in care (i.e., 2 appointments separated by 90 days within 12 months per HRSA-1)

Aim 3: The investigators will conduct mixed methods research (in-depth interviews and focus groups) guided by the Consolidated Framework for Implementation Research and RE-AIM to identify site, patient, provider, and system factors that are barriers and facilitators of processes and outcomes of implementation at the 6 sites randomized to PL.