Tsukihi is a proxy server tailored for the Shinobu protocol. With its help both sides interact through an ASP.NET Core server, using WebSockets. The implementation turned out to be fairly simple, but it did need some specification changes in how the communication is closed (due to differences between TCP and WebSocket). The main purpose of this was to provide an option to get around NAT when port forwarding is not available. However due to the custom nature of the proxy server, and the plans to provide STUN support in the future, I'm not seeing too much opportunity for practical use.