TraceTogether – Community-driven Contact Tracing | Singapore Government Developer Portal
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TraceTogether - Community-driven Contact Tracing

The TraceTogether mobile application is built on the BlueTrace protocol. The open source code has been published on GitHub to provide transparency on data usage.

You may access the TraceTogether Token Technical Write-up here.

Manual contact tracing often requires infected persons to recall the places they have been to and the people they have been in close and extended contact with. A hurdle that contact tracers face in this process is the inability of individuals to recall these details with precision.

The TraceTogether mobile application (available on Android and iOS devices) was developed by GovTech’s Government Digital Services team and the Ministry of Health to complement manual contact tracing efforts. The app uses Bluetooth technology to facilitate community-driven contact tracing through the collection and logging of encounters between users of the mobile app.

A screenshot of the TraceTogether app
A look at the latest version of TraceTogether

How does TraceTogether work?

It relies on Bluetooth technology - The app relies on the communication between Bluetooth-enabled devices to arrive at estimates of the proximity and duration of a user’s contact with other users.

  • TraceTogether approximates the distance between users by measuring the strength of the signals received from other Bluetooth devices (as a general rule, the stronger the signal received, the closer the transmitting device).

  • It also approximates the duration of contact by interpolating successive communications between devices. The more often two devices communicate with each other, the longer they have likely been in the vicinity of each other.

Data is secure and private - The data exchanged is anonymised, encrypted and stored only on users’ devices, and shared with the Ministry of Health if they test positive for COVID-19 . To further protect data privacy, locally stored information is automatically deleted after 25 days. The app will also cease functionality at the end of the outbreak.

Its use is voluntary for the general public - The choice to download TraceTogether is entirely voluntary. Users can give consent through the app to upload the data to a secure government server.

Consent can be withdrawn at any time - Users can also withdraw their consent to data sharing at any time. This is done by requesting for any identification details to be deleted from government servers, making it impossible for any data exchanged with other users’ phones to be linked to them.

At present, TraceTogether has been downloaded over 4.2 million times by Singapore residents.

For more information on BlueTrace and other open-source projects by GovTech, click here.

Click here to learn more about the TraceTogether app.

TraceTogether Tokens

Not everyone has access to mobile devices. While this may only apply to a small percentage of the population, it is crucial that every member of the community can be protected against this pandemic.

An illustration of the TT Token
The TraceTogether Token

TraceTogether Tokens are physical alternatives to the TraceTogether mobile app, and function in a similar manner. These tokens are being progressively distributed to every Singaporean, beginning with the elderly. Users have the option to use the token or the app interchangeably.

What’s in the token?

  • Bluetooth contact tracing - Much like the app, TraceTogether Tokens send and detect Bluetooth signals in order to estimate a user’s contact proximity and duration with other users. Naturally, the app and tokens are able to communicate with each other.

  • Lasting battery life - The battery for the TraceTogether Tokens are designed to run for six to nine months without needing to be charged.

  • No GPS receiver or Internet connectivity - As with the app, no location data is kept by the device in any manner. The token is also incapable of uploading any data automatically since it will not be able to access the Internet. The data will be extracted for contact tracing when a user is confirmed with COVID-19.

  • Data is encrypted - Proximity logs collected by the token will be encrypted. Furthermore, data is only stored on the device for 25 days before being automatically erased.

On 28 June 2020, the first batch of TraceTogether Tokens were distributed to nearly 10,000 vulnerable seniors, i.e. those who are physically frail, living alone or without family support. The Government will progressively distribute TraceTogether Tokens to the rest of the population over the coming months.

For more information on GovTech’s Government Digital Services, visit and

Last updated 01 February 2021

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