If you are looking for a lightweight Protobuf based RPC framework, check out https://connectrpc.com/. It is part of the CNCF and is used and supported by multiple companies: https://buf.build/blog/connect-rpc-joins-cncf

gRPC ships with its own networking stack, which is one reason why those libs are heavy. Connect libraries leverage each ecosystem's native networking stack (e.g. net/http in Go, NSURLSession in Swift, etc.), which means any other libraries that work with the standard networking stack interop well with Connect.