2pTalk.com is built with the Backdrop CMS as it's base. However, the actual "Chat" part of this site is really it's own "App" that can stand on its own and be used on ANY device. I completely built the Chat App from the ground up. It is a very complicated system that works... Great! and Fast! Literally thousands of people can chat (depending on the Server and how much it can handle). The actual "site" is pretty basic but the "Chat" app and the Functionality of the Chat App contains very advanced programming.