Thanks for answers, I will look on it deeply. I found this articles and it looks very promising. What do you think?
https://blog.emerleite.com/using-elixir-genstage-to-track-video-watch-progress-9b114786c604
https://blog.emerleite.com/elixir-video-user-profile-service-for-the-olympics-application-teardown-56ac3e103d1a
GenServers looks very nice for me. They are just upgrade of GenServers.
