Having WebSockets supported in your browser doesn't guarantee they will work for you. Antiviruses, firewalls and HTTP proxies may interfere WebSocket connections, sometimes rendering them useless.Sep 30, 2019 · WebSockets offer bi-directional communication in realtime. WebSockets generally do not use 'XMLHttpRequest', and as such, headers are not sent every-time we need to get more information from the server. This, in turn, reduces the expensive data loads being sent to the server. WebSocket connections can both send and receive data from the browser. Command Line. mitmproxy is your swiss-army knife for debugging, testing, privacy measurements, and penetration testing. It can be used to intercept, inspect, modify and replay web traffic such as HTTP/1, HTTP/2, WebSockets, or any other SSL/TLS-protected protocols.