I'm working on a concept for an efficiency/speed focused networking project.
Any recommendations for low-level languages that support networking that can be run on both windows and Linux with relative easy?
Thanks in advance!

C/C++ will be most likely you route if you need speed. The languages themselves don't have networking, but there are libraries for everything.

@Fast-Nop I'll look into c++, thanks for the recommendation n

@DavRant

Low level networking APIs on both Windows and Linux are pretty similar thanks to Winsock (it's a C API btw).

+1 for C++, if you're serious about speed, you want the speed king.
Also, check out https://github.com/whoshuu/cpr , it's a C++11 implementation of python's requests library - saw it suggested the other day in a comment, and it looks awesome!
Also, you may want to check out ZeroMQ

I can recommend Rust.
It takes a while to get into it,
but it's fast and very memory and thread safe.
The language is designed that way, that if it compiles it will run safe.
No Segfaults!