XAMPP - XAMPP is a free and open-source cross-platform web server that is primarily used when locally developing web applications.
Socket.io - Realtime application framework (Node.JS server)
Apache HTTP Server - Apache httpd has been the most popular web server on the Internet since April 1996
Pusher - Pusher is a hosted API for quickly, easily and securely adding scalable realtime functionality via WebSockets to web and mobile apps.
Apache Tomcat - An open source software implementation of the Java Servlet and JavaServer Pages technologies
SignalR - SignalR is a server-side software system designed for writing scalable Internet applications, notably web servers.