Treating Polysubstance Use Using a Novel Digital Technology

The goal of this clinical trial is to determine the effects of an app to reduce opioid and cocaine use when layered atop methadone treatment as usual among people using both opioids and cocaine. The main questions it aims to answer are: * Do people who use the app remain in methadone treatment longer than people who receive only treatment as usual? * Do people who use the app report using opioids and/or cocaine less often, and do they report better improvements in their quality of life, than people who receive only treatment as usual? * Does using the app more lead to better methadone treatment outcomes among people using the app? Participants in this study will be randomly assigned to receive either the app or methadone treatment as usual. Participants randomly assigned to the treatment as usual group will receive access to methadone services as normally provided, including scheduled access to medications, information about the consequences of opioid and other drug use, and any onsite services (including group based interventions and/or 12-step programs). Those randomized into the app-using group will receive all the same services as the treatment as usual group, but will also be given a phone with the app already installed, or will have the app installed on their existing phone if they already have one. At random times throughout the week, the app will ask participants to submit drug tests for opioids and cocaine, which participants will be able to do remotely without having to physically "go to" a testing site. For each test that demonstrates the participant hasn't used opioids or cocaine, the participant will be rewarded with money directly into a debit card. Participants will also be able to earn rewards for picking up treatment-related medications, attending onsite appointments, and other treatment-related activities.