Good question. Building for extreme scale constrained the possible architectural space. For a high level overview of the application architecture, refer to the

Good question. Building for extreme scale constrained the possible architectural space. For a high level overview of the application architecture, refer to the seperate comment here in this thread. It started initially by realizing that our app, Slyp, requires extremely distributed invoice and coupon processing as we started rolling out. So the architecture must handle such scale without issues. This lead to persisting every incoming request (for commands) from the frontend and dismissing them only to be informed later of continuing with the status. This avoids processing requests when the system is overloaded with high traffic. So naturally the minimum is a log style ordered persistence. Initially kafka. Later our own Monolog built in rust which is substantially faster for our workloads and zero jvm and low memory and can run on servers and mobile alike. Naturally the right point to consume this was into the command ingestion point in the Feature Architecture as noted in the other comment. This expanded the capability to all feature invocations including inter and intra service feature invocations. This then progressively evolved into a much capable engine at which point we realized, this is a durable execution engine for command features but as a minor part of the whole Feature Architecture itself.