[neoeno]

I was developing some architecture training recently and had this very same question. It’s not easy to find realistic architectures.

The best I found was the German contact tracing app — Corona Warn App. It was done by a group of consultancies in collaboration with the German govt, and went from inception to launch in around fifty days — largely if not totally open source.

Here’s the repo that has all the architecture in: https://github.com/corona-warn-app/cwa-documentation

It’s got full git history so you can see it evolve over time, along with the implementations (also on Github).

There’s a pretty fascinating short talk by one of the people who led the project on youtube too — more about the process side though: https://youtu.be/5y1sHSkPWRg?t=1770