No matter load, there is a need for complexity for this certification.
Not all employees log in daily. For a scheduling app, most people check a few times a week, but not every day.
Daily active users (DAU) = around 10,000 to 20,000
Peak concurrency (users on at the exact same time) = generally between 1,500 to 2,000 at busy times (like when new schedules drop or at shift start/end times)
Average concurrent users at any random time = maybe 50 to 150
Why cloud costs can add up even for us:
Extensive use of real-time features and complex labour rules mean the app needs to handle a lot of data processing and ultimately sync into salary systems.
An example:
Being assigned to a shift has different implications for every user. It may trigger a nuisance bonus, and such a bonus could further only be triggered in certain cases, such as when you had the shifts assigned compared to when it start time.
Lastly, there is the optimizing of a schedule why is computationally expensive.