By Ilya Grigorik on August 26, 2011 Server-Sent Events (SSE) have long been in the shadow of the much more often talked about WebSockets API. While WebSockets can be thought of as the "TCP for the web", then SSE is best described as the "HTML5 replacement for Comet)". Question is, do we really need both? WebSockets allow bi-directional communication and to do so, they piggyback on the original HTT