Hi Alvin, I’m not familiar with Waitress so I can’t speak to it’s specific implementation. However, Prefect tries in all ways to be backend- and execution- agnostic, and we require all functionality to work in a global, distributed environment. As a result, we ship very few stateful features in Core except when we know for sure that they can work in a shared memory space, as with a single thread. However, for caching support across processes, time, and even flows, you may want to take a look at Prefect Cloud, which was designed to support that use case.