Telegram

 Telegram was launched in 2013 by the brothers Nikolai and Pavel Durov. Previously, the pair founded the Russian social network VK, which they left in 2014, saying it had been taken over by government. Pavel Durov sold his remaining stake in VK and left Russia after resisting government pressure. 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. Telegram Messenger states that its end goal is not to bring profit, but it is not structured as a non-profit organization.

Telegram is registered as a company in the British Virgin Islands and as an LLC in Dubai. 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. After Pavel Durov left Russia in 2014, he was said to be moving from country to country with a small group of computer programmers consisting of 15 core members. While a former employee of VK claimed that Telegram had employees in Saint Petersburg, Pavel Durov said that the Telegram team made Berlin, Germany its headquarters in 2014, but failed to obtain German residence permits for everyone on the team and moved to other jurisdictions in early 2015. Since 2017, the company has been based in Dubai. It has a complex corporate structure of shell companies to be ahead of government subpoenas.

Telegram apps receive monthly updates. Users can report apps' issues and recommend development ideas on the dedicated "Bugs and Suggestions" platform.

Telegram accounts are tied to telephone numbers and are verified by SMS or phone call. Account creation requires an iOS or Android device regardless of the platform intended to be used. Users can add multiple devices to their account and receive messages on all of them. Connected devices can be removed individually or all at once. The associated number can be changed at any time and when doing so, the user's contacts will receive the new number automatically. In addition, a user can set up a username as an alias that allows them to send and receive messages without exposing their phone number. Telegram accounts can be deleted at any time and they are deleted automatically after six months of inactivity by default, which can optionally be changed from 1 month at the shortest up to 12 months at most with a range between. Users can replace exact "last seen" timestamps with broader messages such as "last seen recently".

The default method of authentication that Telegram uses for logins is SMS-based single-factor authentication. A one-time passcode that is sent via SMS to the user's phone number is required to log into the account by default. Users also have the option to create a password as a form of two-step verification.

Telegram allows groups, bots and channels with a verified social media or Wikipedia page to be verified but not user accounts.

Accounts of users who purchased Telegram's Premium subscription are marked with a star emoji, which the users can change to any emoji of their choice.