Long-Polling vs WebSockets vs Server-Sent Events Long-Polling, WebSockets, and Server-Sent Events are popular communication protocols between a client like a web browser and a web server. First, let’s start with understanding what a standard HTTP web request looks like. Following are a sequence of events for regular HTTP request: Client opens a connection and requests data from the server. The server calculates the response. The server sends the response back to the client on the opened request. HTTP Protocol Ajax Polling Polling is a standard technique used by the vast majority of AJAX applications. The basic idea is that the client repeatedly polls (or requests) a server for data. The client makes a request and waits for the server to respond with data. If no data is available, an empty response is returned. Client opens a connection and requests data from the server using regular HTTP. The requested webpage sends requests to the server at