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COVID Alert is now retired: For more information, visit the Government of Canada COVID Alert home page.

As a standard practice, CDS works in the open, which includes publishing our service documentation. This site is a summary of our work and we welcome your feedback, comments or questions via

COVID Alert is an exposure notification (EN) service developed by the Canadian Digital Service in partnership with Health Canada. It launched in the province of Ontario on July 31, 2020, and became available in nearly all Canadian provinces and territories by November of that year, excluding Alberta, British Columbia, Nunavut, and Yukon.

COVID Alert is based on the open source CovidShield app developed by volunteers from Shopify. The Ontario Digital Service also contributed to the development of COVID Alert, and the Canadian Centre for Cyber Security and Blackberry (on a pro bono basis) provided security assessments and reviews.

Exposure notification is a framework developed by Apple and Google to facilitate digital contact tracing while protecting users’ privacy. As with all other implementations of EN, COVID Alert uses Bluetooth to broadcast and receive randomly-generated IDs to and from the smartphones of other COVID Alert users within the user’s vicinity. If a user later tests positive for COVID-19, they can enter a one-time key to flag their IDs within a specific timeframe, allowing others to be notified of a possible exposure without identifying the user or their device.

How the COVID Alert app works (video)

Service overview

COVID Alert is a service made up of an ecosystem of products which enable it to function. Although the app is the most public aspect of the service, it is only one component of the service within the COVID Alert ecosystem. The three main components of COVID Alert are:

In order to deliver this complex service, CDS formed three interdependent product teams responsible for building and maintaining their respective component within the COVID Alert service.

Service design

The COVID Alert service is designed to augment contact tracing without replacing existing processes. Without replacing existing touchpoints within the manual contact tracing, COVID Alert introduces new touchpoints within the contact tracing process that are only applicable to people who have downloaded the COVID Alert app onto their mobile devices. The two main touchpoints introduced are:

  • One-time key: an alphanumeric code that is given to app users who have tested positive for COVID-19. The one-time key was generated from the server API that was connected to the healthcare portal or directly to a case management system operated by health authorities.
  • Notification of possible exposure: the notification sent to mobile devices that have been in close contact with another device that has entered a one-time key. This notifies somebody that they have been potentially exposed to someone who tested positive for COVID-19, and provides instructions on what to do next depending on the guidelines of the province where they are located.

Generic Service Map

Generic Service Map

This is a service map for Exposure Notification (EN) in Canada which showcases the various actors, touchpoints, and stages within the exposure notification service.

The actors are the people involved within the exposure notification service. The main actors within the service are the patient who has tested positive for COVID-19, the tester who administers tests for COVID-19, the lab technician who determines results from COVID-19 tests, the contact tracer and the exposed person who has been in close contact with a patient who tested positive.

Touchpoints are the points of interaction within the exposure notification service. Existing touchpoints outside of the exposure notification are the testing centre, the lab where test results are determined, the test results of the patient, and the phone call used to communicate with patients and exposed persons. New touchpoints introduced with the launch of the EN service are the awareness campaign to get people to download app, the COVID Alert app which notifies people who have been potentially exposed, the COVID Alert portal used by contact tracer to generate a one-time key, and the one-time key which is an alphanumeric code generated entered into the COVID Alert app that enables exposure notification.

The stages of the EN service reflect how the actors interact and communicate through the various touchpoints. The important stages to note are the one-time key generation and the exposure notification, which show that the one-time key hand-off between contact tracer and patient is the integral touchpoint for the exposure notification to work. These two stages showcase the fact that the exposure notification service augments existing contact tracing without replacing the existing processes like testing and manual contact tracing.

COVID Alert is a voluntary service for provinces and territories to adopt, and for the people within them to download and use. It adopts privacy-by-design for app users and provides flexibility for provinces to implement the service within their healthcare system.

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