User-Controlled Visibility: Telegram empowers users with granular privacy settings to control who can see their phone number:
"Everybody": Your number is visible to anyone on Telegram.
"My Contacts": Only users in your Telegram contacts list (who also have your number in their phone) can see it.
"Nobody": No one, not even your contacts, can see your phone number on your Telegram profile. This is the strongest privacy setting for your number.
"Who can find me by my number?": This separate setting allows you to control whether others can find your Telegram profile by searching for your phone number. This can be set to "Everybody," "My telegram number database Contacts," or "Nobody," further limiting discoverability based on your number.
2. Usernames for Anonymity and Discoverability:
Decoupling Identity: This is a cornerstone of Telegram's privacy by design. By allowing users to set a public username (e.g., @YourUsername), Telegram provides a mechanism for others to find and contact you without ever needing or seeing your phone number.
Primary Interaction Method: In many public contexts (groups, channels), interactions occur via usernames, providing a layer of pseudonymity. Your phone number is never revealed unless you explicitly choose to.
Fragment (+888 Numbers): Telegram's introduction of anonymous, blockchain-based +888 numbers (via Fragment) is the ultimate extension of this. It allows users to create a Telegram account without any link to a traditional telecom service or personal identity, while still fulfilling the "phone number required" principle.
Opt-in Feature: Telegram only accesses your device's contacts with your explicit permission.
Limited Data Upload: When enabled, Telegram uploads only phone numbers and names from your address book. It does not collect other personal details (emails, addresses, etc.).
Purpose-Limited Use: This data is used solely for the purpose of identifying your existing friends on Telegram and notifying you when they join. It's not used for advertising or shared with third parties.