Long polling is a technique for maintaining a persistent connection between the client and the server. It is used to push data from the server to the client. The connection is maintained after a request for new information has been made by the client to the server, until the data becomes available on the server and it is ready to send it to the client. The connection is closed when the server has sent the data to the client or a connection timeout occurs. The flow of long polling is: The client sends a request for information to the server. The server holds the client’s connection until new data is available. The server responds to the client as new information becomes available.