The general rule of thumbs is that Websocket are cheaper if you want long connection with states to maintain (you only need to identify once) or have a lot of s

The general rule of thumbs is that Websocket are cheaper if you want long connection with states to maintain (you only need to identify once) or have a lot of small messages. However, you have a low number of requests, or big requests, REST is going to be faster. But as usual, it depends of your implementation and your constraint. After all, facebook is using polling if I recall.