We have a bunch of testers interfacing with hardware that used to run one big monolithic app that would handle everything from scheduling tests, reporting results, grabbing test artifacts, interfacing with hardware APIs, etc. Rather than move everything over at once, we are splitting out each service and wrapping it in Pyro4, then upgrading them one at a time. We also had a lot of test tooling in legacy java/.net systems, but Pyro4 can wrap those too with (IronPython/Jython)

It works nicely in about 95% of use cases with minimal overhead, but there are some gotchas to be aware of (like all strings being serialized as unicode). If we were architecting the whole thing from scratch, some of it might have made more sense with something like gRPC, but it is still a neat tool to have in your toolbox.