TraceTogether adopts a community-driven approach where participating devices exchange proximity information whenever an app detects another device with the TraceTogether app installed.
We use the Bluetooth Relative Signal Strength Indicator (RSSI) readings between devices across time to approximate the proximity and duration of an encounter between two users. This proximity and duration information is stored on one's phone for 21 days on a rolling basis — anything beyond that would be deleted. No location data is collected.
If a person unfortunately falls ill with COVID-19, the Ministry of Health (MOH) would work with them to map out their activity for past 14 days, for contact tracing. And if the person has the TraceTogether app installed, they can grant MOH to access their TraceTogether Bluetooth proximity data — making it quicker for MOH to contact people who had close contact with the infected individual, to provide timely guidance and care.