What user detail does Telegram Login keep hidden from website owners?
Answer
phone number
Telegram Login keeps the user’s phone number hidden from website owners by default.
Telegram Login was designed to provide a convenient social sign-in without automatically exposing the phone number used to create a Telegram account. In the original login-widget model, the website could receive public profile details such as the user’s name, username, and profile picture, while the phone number remained private.
That privacy distinction is easy to miss because a phone number is central to Telegram account registration and account recovery. It does not mean the number can never be shared: Telegram’s newer login systems can request a phone number with the user’s permission, and Telegram’s privacy settings separately control who can see it.
The other options describe information that the login service may provide as part of the user’s public profile. “Display name” and “profile picture” are profile fields, while a “username” helps identify the account publicly. The hidden detail in the classic Telegram Login description is therefore the phone number.