TraceTogether (Singapore)

One of the first contact tracing apps to be developed as the pandemic spread throughout east Asia was by the government of Singapore, which came up with TraceTogether, a Bluetooth-based contact tracing app that arrived long before Apple and Google formed their partnership.

TraceTogether is notable for not only being an early entry, but also for the remarkably privacy-conscious approach it took to its design — an approach that some other countries have been resisting in their hunger to get as much data as possible in fighting the spread of SARS-CoV-2. The government of Singapore also chose to release the app as open source in the hopes that other countries would be able to benefit from its head start.

Instead of collecting personal information and location data, TraceTogether used only phone numbers and randomized personal IDs, stored in a secure registry. Phones running the app then used Bluetooth to ping other nearby phones so that they could record IDs of everybody a person who had been in contact with. However this information remains stored only on the user’s own phone, unless they’re later diagnosed with COVID-19, at which point they’re asked to send their logs to the Singaporean government so that they can be analyzed to determine who that person has come into contact with, and notify them to either self-isolate or get tested.

The catch? Like most apps that you run on your iPhone, TraceTogether actually has to be actively running, with your screen unlocked, in order to collect contact tracing information.