Users can exchange messages encrypted end-to-end, self-destructing messages, along with photos, videos, stickers, and files of any type up to 1.5 GB in size.
Telegram is run by a German nonprofit organization backed by entrepreneur and philanthropist Pavel Durov. Its client code is open-source software, while currently, its server-side code is proprietary. Also, software is available from independent developers who make use of the Telegram API.
Download it here : https://telegram.org/