Most use a websocket library like sockjs or socket.io which uses websockets and falls back to long polling if there's an issue with that. Some IRC servers are

Most use a websocket library like sockjs or socket.io which uses websockets and falls back to long polling if there's an issue with that. Some IRC servers are starting to implement native websockets but that introduces several issues, so many networks use a websocket gateway to accept websockets to their network, such as https://github.com/kiwiirc/webircgateway https://github.com/kiwiirc/webircgateway Then for IRCv3, most clients these days do support their specs in some form of way, and it's growing :)