Hi there,
Developing the game itself should be relatively easy, but I never played backgammon. Just watched a video on youtube to get a basic understanding of the rules and I was able to understand them for the most part, I'll watch a few more videos if shortlisted to fully understand them.
The game would have a node.js backend so that moves can be transmitted in real time, and it would expose an API allowing the game to be included into any website.
Regards,
Julijan