TraceTogether, a mobile app to support contact tracing efforts developed by the Government Technology Agency (GovTech), in collaboration with the Ministry of Health (MOH), was launched on Friday, Mar. 20.

In the three days since the app was launched, it has been installed by more than 620,000 people so far, said Minister for Foreign Affairs Vivian Balakrishnan in a Facebook post on the morning of Monday, Mar. 23.

About TraceTogether

TraceTogether helps with contact tracing by sending short-distance Bluetooth signals between phones of participating TraceTogether users in close proximity with each other.

The app estimates the distance between the app users, and the duration of such encounters.

Records of these encounters are encrypted and stored locally on each user’s phone for 21 days, which covers the incubation period of the virus.

Thus, TraceTogether users interviewed by MOH as part of contact tracing effort have the ability to consent to sending their TraceTogether data to MOH.

MOH is then able to decipher the data and obtain the mobile numbers of the user’s close contacts within a period of time.

This facilitates the contact tracing process, and enables contact tracers to inform TraceTogether users who are close contacts of Covid-19 cases more quickly.

More than 620,000 users

Vivian said in his Facebook post that TraceTogether had been installed by more than 620,000 people thus far, in the three days since it was launched.

Jason Bay, Senior Director at the Government Digital Services team at GovTech, posted a photograph on Facebook on Mar. 21 showing his team in the operations room.

He said that new users were signing up at the rate of several thousand per minute, with some bursts of almost one hundred per second.

At the time of his post, which was less than 24 hours since the launch of TraceTogether, "several hundred thousand users" had already signed up, he said.

TraceTogether to be open sourced

In his Facebook post on Monday (Mar. 23), Vivian announced that the TraceTogether app will be open sourced.

He added that GovTech is "working around the clock" in order to finalise protocol reference documents and reference implementation in order to allow others to create their own versions of TraceTogether.

He wrote:

"We believe that making our code available to the world will enhance trust and collaboration in dealing with a global threat that does not respect boundaries, political systems or economies.

Together, we can make our world safer for everyone."

The TraceTogether app and its counterparts, once they are developed, are all part of the implementation of the BlueTrace protocol, wrote Vivian.

According to the BlueTrace Manifesto, the need for an international adoption of contact tracing apps such as TraceTogether is because of the globalised world we live in:

"Covid-19 and other novel viruses do not respect national boundaries. Neither should humanity's response.

In a globalised world, with high volumes of international travel (until very recently) any decentralised contact tracing solution will need mass adoption to maximise network effects.

We believe that TraceTogether and its sister implementations should be inter-operable, and that's what we're building towards."

You can read Vivian's full Facebook post and more about TraceTogether and BlueTrace here:

Top photos via Syahindah Ishak and screenshot by Zheng Zhangxin.