We use Python server-side and the Python implementation of Google protocol buffers is extremely slow.

Here are two alternative Python protobuf implementations. They're each about 15x faster than the pure Python implementation from Google.

fast-python-pb - codegen wrapping Google's C++ protobuf implementation. https://github.com/Greplin/fast-python-pb

lwpb - non-codegen using a protobuf implementation in C. (disclaimer: I'm an author) https://github.com/acg/lwpb