The undoubtable mention of SockJS will appear multiple times in this thread. Socket.io has been plagued with scalability issues since its original release (can'

The undoubtable mention of SockJS will appear multiple times in this thread. Socket.io has been plagued with scalability issues since its original release (can't speak on the new version) and Engine.io is suppose to be fix that. The main difference between SockJS & Socket.io is their connection establishment. SockJS begins by attempting to use Websockets and regress to long polling while Engine.io starts with long polling and slowly works its way up to Websockets. For a good debate on this with the creator of SockJS: https://groups.google.com/forum/#!topic/sockjs/lgzxVnlth54 https://groups.google.com/forum/#!topic/sockjs/lgzxVnlth54