The Basque Government and the Basque telecommunications company EricTil developed a smartphone application to help control the spread of COVID-19. Individuals in the Basque country who download the app are asked to provide information on their health status as well as any close connections they have with family, friends, and co-workers. The app then regularly contacts individuals and asks them if they have any symptoms consistent with COVID-19. If a person contracts or is deemed likely to have contracted COVID-19, an alert is sent to people in that person’s immediate contacts along with recommendations on prevention techniques and contact information for health professionals. The information is also anonymized and provided to relevant health researchers, who can use the information to detect transmission.