I wanted to use MsgPack, but msgpack4nim doesn't look well maintained. I also had an issue when trying to use it.
Is there any other serialization module that's optimized for minimal size and high speed?
I've used msgpack4nim for serialization between Nim & Python without any issues.
Sometimes a repository is just "done" - the msgpack protocol is not evolving anytime soon - so there's not much activity to be done.
Otherwise there's https://github.com/PMunch/protobuf-nim .
If you want Nim <-> Nim serialization then maybe plain Json serialization such as https://github.com/treeform/jsony can do the trick
If you are doing nim <-> nim I use https://github.com/treeform/flatty. When I do nim <-> some thing else (like python) I use https://github.com/treeform/jsony
If you are doing real time, interactive, game like networking I also recommend https://github.com/treeform/netty (but not if you are transferring files) for networking.
Both can be improved by compression, I recommend https://github.com/guzba/supersnappy for nim <-> nim or https://github.com/guzba/zippy for nim <-> some thing else (like python).
For nim <-> nim I would use netty`+`flatty`+`supersnappy (super fast) For nim <-> python I would use regular tcp +`jsony`+`zippy` (pretty easy)