I assumed this was doing some LAN-based communication (multicast perhaps, or webRTC), but it looks like it's just a standard chat server that generates one room per IP address.<p>It'd be interesting to extend the idea to do literally local chat though. It'd be effectively serverless, super resilient, and impossible to externally access (nice for all sorts of compliance concerns). In theory it's all doable, but the initial bootstrapping to find other people on your network from within a web app is tricky...