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Our Mission

Slow the spread of infectious diseases like COVID-19 with crowdsourced data.

COVID Watch aims to empower people to protect their communities from COVID-19, without sacrificing their personal privacy. We are building a decentralized, privacy-preserving app that will alert users if they have been exposed to COVID-19.

Our Project

COVID-19 has a relatively long infectious incubation period, averaging five days but potentially up to two weeks, during which there may be asymptomatic transmission. In other words, there may be a period of time in which people who carry COVID-19 don't necessarily show symptoms and may not even realise they are infected, but are still capable of infecting others. This makes it harder for health professionals and epidemiologists to trace who has come into contact with infected persons ('contact tracing'), which in turn makes the virus more difficult to effectively contain.

Many people, however, now carry smartphones, and Bluetooth-enabled phones can see which other phones they're in proximity to. This could be used to rapidly and automatically implement a notification system similar to contact tracing, but anonymous. This would help to limit the spread of COVID-19 and other infectious diseases. We can use Bluetooth connections between users to enact cryptographically secure contact tracing and alerting them if we learn that they have been exposed to COVID-19, without collecting the identities, exposure, or infection status of any users.

Our Principles

(1) Privacy: Tracking is a sensitive issue, especially in a project like ours that necessitates some degree of data sharing to be effective. This is why we're absolutely committed to building an app that goes out of its way to respect and preserve your privacy.
In fact, that's a big part of why we're building this app in the first place. Superficially similar (but far more invasive) projects are already being trialled around the world - we decided that it would be a good idea to have a transparent, not-for-profit alternative that has privacy baked into it from the very beginning.

(2) Efficacy: With such high stakes, we want to be absolutely sure that we're using our time and energy wisely. We aren't aiming to take focus away from more directly impactful work like vaccine development or front-line healthcare, and we recommend that you only help our project if it doesn't detract from more important work elsewhere. Additionally, we're on the lookout for overlapping work by groups with similar values, to avoid reinventing the wheel.

(3) Altruism: This project has its roots in effective altruism: doing the most good that we can with what we have. We're not here to make a profit, get famous, or push an ideology. We're a group of volunteers doing this out of a desire to make the world a better place - for us, and for you.

Our Timeline

We've recruited a strong team, successfully developed an internal proof of concept, and formalised a strong theoretical basis for what we want to do. Our next steps are tentatively planned as follows, contingent on no insurmountable obstacles appearing:

One to Two Weeks (by mid-April 2020): Further refine our beta app. Liaise with public health agencies to implement systems to validate diagnoses. Finalize inter-app standards.

Two to Four Weeks (by May 2020): Roll out the app in impacted communities as a pilot program in conjunction with public health agencies, refining and adding functionality as needed. Assess efficacy and make adjustments as needed.

Our People

An overview of many members of our team, including our advisors, can be found here.

If you're interested in joining us or helping out, have a look at our collaborations page for more information.

Similar Projects

Our project is one of a constellation of efforts exploring apps for community contact tracing. We are actively collaborating with other teams around the world, exchanging code and ensuring system and data interoperability. Our hope is that any progress made by COVID Watch will benefit many projects.


Our project! An app for voluntary, decentralized, privacy-preserving alert system, which is an intervention that is expected to have the same benefits as contact tracing. Our Bluetooth proximity network system notifies users of potential close contact exposure. Our team was the first to open source Android, iOS and cross-communication between devices for Bluetooth contact alerts on March 17, 2020. Check out our white paper for more information.

Active Collaborations:

CoEpi: Community Epidemiology In Action

The CoEpi team are working on an app for community contact tracing, in which users would be able to report symptoms and likely contagiousness, whether they have a cold, flu, COVID-19, or any other contagious disease. We are collaborating with them on a shared, privacy-preserving database design.

PrivateKit: Safe Paths

Built by a team at MIT, Safe Paths focuses on an anonymized 28-day GPS trajectory, rather than bluetooth contact events.The team is leveraging their history of research on privatizing data. They are helping us to test our Bluetooth protocol.


This app is the first nationwide deployment of Bluetooth-enabled contact tracing. It was released by the Singaporean government on March 20, 2020. The app uses a similar approach to COVID Watch. We have been in touch with the TraceTogether team and are ready to adapt their code to our project as soon as it is open-sourced.

Other Projects

We wanted to contrast COVID Watch with a few other projects, but in the course of compiling this page it’s become clear that we won’t be able to successfully maintain a list of all the rapidly-proliferating projects in this space. For some efforts that are trying to do that, please see:

We know there are many projects in this space, and we’re striving to provide interoperable libraries that other projects will be able to use.

For all inquiries, please contact us at

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