Telegram is a freeware, cross-platform, cloud-based instant messaging (IM) software and service. The service also has video calling, VoIP, file sharing and other features. It was initially launched for iOS on 14 August 2013 and Android in October 2013. The application servers of Telegram are distributed worldwide to decrease data load, while the operational center is currently based in Dubai. Various Telegram client apps are available for desktop and mobile platforms including official apps for Android, iOS, Windows, macOS and Linux, as well as for the now-discontinued Windows Phone. There is also an official web interface and numerous unofficial clients that make use of Telegram's protocol. All of Telegram's official apps are open source.
Telegram provides end-to-end encrypted calls and optional end-to-end encrypted "secret" chats between two online users on smartphone clients, whereas cloud chats use client-server/server-client encryption. Users can send text and voice messages, animated stickers, make voice and video calls, and share an unlimited number of images, documents (2 GB per file), user locations, contacts, and music. In January 2021, surpassed 500 million monthly active users. and was the 8th most downloaded app worldwide in 2020.
Telegram was launched in 2013 by brothers Nikolai and Pavel Durov. Previously, the pair founded the Russian social network VK, which they left when it was taken over by the Mail.ru Group. Nikolai Durov created the MTProto protocol that is the basis for the messenger, while Pavel Durov provided financial support and infrastructure through his Digital Fortress fund, with partner Axel Neff joining as a second co-founder. The company and the app were started in Russia in 2013 and later moved to Germany. Telegram Messenger states that its end goal is not to bring profit, but it is not currently structured as a non-profit organization.
Telegram is registered as both an English LLP and an American LLC. It does not disclose where it rents offices or which legal entities it uses to rent them, citing the need to "shelter the team from unnecessary influence" and protect users from governmental data requests. Pavel Durov said that the service was headquartered in Berlin, Germany, between 2014 and early 2015, but moved to different jurisdictions after failing to obtain residence permits for everyone on the team. Durov left Russia and is said to be moving from country to country with a small group of computer programmers consisting of 15 core members. According to press reports, Telegram had employees in Saint Petersburg. The Telegram team is currently based in Dubai.