In addition Telegram provides end-to-end encrypted calls and optional end-to-end encrypted 'secret' chats between two online users on smartphone clients.

This data is also encrypted at rest, but can be accessed by Telegram developers, who hold the encryption keys. An announcement at that time included a promise to implement secure group video calls later in 2020.The default messages and media use client-server encryption during transit. As of April 2020, Telegram had 400 million monthly active users. The service also provides APIs to independent developers. Telegram's client-side code is free software, whereas its server-side code is closed-source and proprietary. Users can send messages and exchange photos, videos, stickers, audio and files of any type.

Telegram client apps are available for Android, iOS, Windows Phone, Windows, macOS and GNU/Linux and originated in Russia in 2013. Telegram is a cloud-based instant messaging, videotelephony and voice over IP service with end-to-end encryption for secret chat only.

Install telegram app