To do this we took a different approach than the automated contact tracing apps relying on GPS or Bluetooth, which require a large adoption from the general population to work. Instead, we noticed that many of our friends around us who had (or had symptoms of) Covid often did not notify those they met during their infectious period.

This was because they either didn't know this was important, did not know the precise dates of said infectious period, or sometimes just because writing such a message can be a bit touchy, which adds too much social friction to the process.

So to address this we built a simple solution, which doesn't require any fancy tech: we simply took the questionnaire used by human contact tracers and put it in a user-friendly, digital format. We then help people remember (Turbotax-style) who they crossed paths with, and suggest pre-written messages they can send in one click.

We launched this in France back in May when lockdown ended there, and were able to generate hundreds of alerts, so we made an international version. Let me know if you have any questions or feedback!