https://capnproto.org/ 

This seems like it could be a good match for Nodes and potentially other projects.
One obvious goal is cross-platform serialization without having to reinvent it myself.

For Nodes it could be used at the inter-nodes layer, to structure packets between nodes.
Nodes server should not care about their payload, with the exception that ideally as a service nodes should provide both a byte stream and a packet/message oriented stream.