Telegram is an instant messaging system focusing on privacy and multi-platform availability. Telegram clients exists for both mobile (Android, iOS, Windows Phone) and desktop systems (Windows, Mac OS X, Linux). Telegram users can exchange messages encrypted end-to-end, self-destructing messages, along with photos, videos and files of any type up to 1.5GB in size. Telegram is run by a German nonprofit organization backed by entrepreneur and philanthropist Pavel Durov. It open-sourced its client code, while server-side code is currently proprietary. Software is also available from independent developers who make use of the Telegram API.