California MEPS Hub

Inclusion Criteria: RCT Participants * Assigned male at birth * Ages 18 - 59 * Was released from incarceration in the previous 12 months (incarceration is defined as a stay in jail, prison, or detention centers for over 24 hours) * Reports an SUD diagnosis or seeking SUD services at any time in the 24 months prior to enrollment * During the 24 months prior to enrollment, either: 1. Reports intercourse with a person assigned male at birth 2. Reports injection drug use * Has not received an HIV diagnosis (based on self-report) * Possesses a smartphone or plans to obtain one * Plans to reside within designated jurisdictions (counties) for the 9 months following enrollment CBO and agency staff participating in implementation surveys or interviews * \>=18 years of age * Employed at a study site or otherwise involved with intervention implementation and/or maintenance OR works at an agency in the counties where the study is taking place (Los Angeles, Riverside, San Bernardino, and Alameda counties, California). * Willing to provide informed consent for participation. Exclusion Criteria: RCT Participants: * Does not have a smart phone and is not willing to obtain one * Is not able to speak and understand English * Has insufficient reading skills to operate a mobile application on a cell phone CBO participating in implementation interviews \- n/a