• Erlang, FreeBSD, Yaws, Lighttpd, PHP, and XMPP are the programming languages used by Telegram. The real-time chatting component is implemented in Erlang. Along with PHP, FreeBSD is responsible for the app to desktop transfer or Web WhatsApp.
• XMPP is the technology that allows you to send messages, display your online presence, route traffic, and much more. WhatsApp's backbone is referred to as this. The other two are web servers that improve the speed, security, and flexibility of the system.
• Furthermore, for the iOS app, two different languages are used: Objective-C for the most part and Swift for the rest. AngularJS and NodeJS were used to build the web app. WhatsApp, on the other hand, makes use of PHP. Multiple languages are used in the desktop software. Objective-C, C, C++, and Qt are a few of them. Misconception about speed 

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