Is it possible to capture localhost (client and server) websockets communication?In my case, in the client side I am using javascript code to connect to the websocket server, that it is started using java language.
Yes, it is possible to capture websocket traffic with Fiddler Classic. I've attached a screenshot of the product where you can see the websocket communication between a Node.js server running on the localhost and a local webpage opened in the browser. In order to see the websocket traffic, you must ensure the requests sending from your client app respects the proxy set by Fiddler Classic. After that, just locate the request marked with the small WebSocket icon and double-click it.