[drdaeman]

What about https://github.com/GreatFruitOmsk/protobuf-py3?

I don't really see what could be non-trivial about Protocol Buffers. The encoding's simple to the extent one could probably hack a minimal working implementation over a weekend or another. That is, unless you need not the data format, but the very exact Google's library (which, to my tastes, is severely unpythonic and has an quite weird and bloated codebase - which is probably the issue with porting, but sadly is a dependency for some other libraries).

[rch]

Yes, sticking with Google's library is the limitation. Without the official library, there are probably better ways forward anyway.