Agreed, on my searching a VM to run foreign code is limited. You need a system that can run compiled code in order to be efficient, and interpreted is much more

Agreed, on my searching a VM to run foreign code is limited. You need a system that can run compiled code in order to be efficient, and interpreted is much more common but then you run into FFI issues. As to serialization of an interpreted it’s annoying that on embedded I’d have to send the letters “f” “o” “o” “(“ “x” “)” “;” which obviously kills some of the point here. mJS does the VM and FFI part OK, but I didn’t like some of the way it handled JS types coming back to C, it wasn’t clear for example that a C defined value passed in would return as a signed JS/NaN until converted.