Was looking at RPC framework for a project, in the end I went with Apache Thrift since at that time there was no Python 3 support for gRPC [1]. IIRC Thrift also lacks support for my project's Python version (3.5) but at least I can use thriftpy [2].

https://github.com/grpc/grpc/issues/282 https://github.com/eleme/thriftpy