С++, TCP/IP

 https://habr.com/ru/post/503432/

https://coderoad.ru/32887310/%D0%9F%D1%80%D0%BE%D1%81%D1%82%D0%BE%D0%B9-%D0%BA%D0%BB%D0%B8%D0%B5%D0%BD%D1%82-%D1%81%D0%B5%D1%80%D0%B2%D0%B5%D1%80-TCP-c

https://www.bogotobogo.com/cplusplus/sockets_server_client.php

https://www.cyberforum.ru/cpp-networks/thread1996810.html

https://www.geeksforgeeks.org/socket-programming-cc/

https://www.geeksforgeeks.org/tcp-server-client-implementation-in-c/

https://github.com/elhayra/tcp_server_client

https://riptutorial.com/cplusplus/example/23999/hello-tcp-server

WebSockets

https://github.com/zaphoyd/websocketpp

https://coderoad.ru/9528811/Websocket-%D0%BA%D0%BB%D0%B8%D0%B5%D0%BD%D1%82-%D0%B2-C

https://stackoverflow.com/questions/9528811/websocket-client-in-c

https://istarik.ru/blog/programmirovanie/73.html

https://docs.websocketpp.org/md_tutorials_utility_client_utility_client.html

https://docs.websocketpp.org/

https://www.boost.org/doc/libs/1_70_0/libs/beast/doc/html/beast/quick_start/websocket_client.html

https://doc.qt.io/qt-5/qtwebsockets-examples.html

https://devblogs.microsoft.com/cppblog/c-rest-sdk-websocket-client/

https://rstudio.github.io/websocket/