1. Telegram Does NOT Share Your Phone Number with Third Parties for Marketing or Advertising
Core Principle: Telegram's fundamental privacy principles, as stated in their official Privacy Policy, are:
"We don't use your data to show you ads."
"We only store the data that Telegram needs to function as a secure and feature-rich messaging service."
No Sale of Data: Telegram has consistently maintained that it does not sell or share your personal data, including phone numbers, with marketers, advertisers, or any "mafia family 'family of companies'" (as they playfully put it).
2. Telegram Does NOT Share Your Phone Number with Other Users Without Your Explicit Control
You Control Visibility: Telegram provides robust telegram number database privacy settings that give you complete control over who can see your phone number on your profile. You can set this to:
Nobody: Your phone number will never be visible on your profile to any other user.
My Contacts: Only users who you have added to your Telegram contacts (who are also in your phone's address book) can see your number.
You Control Discoverability: You also control "Who can find me by my number?". Even if your number is hidden on your profile, you can decide if someone can find you by searching for your number (e.g., only "My Contacts" or "Nobody").
Usernames for Anonymity: You can use a username (@YourUsername) to communicate with others without ever revealing your phone number.
3. Telegram May Share Your Phone Number with Law Enforcement Under Specific, Limited Circumstances
This is the area where Telegram's policy has seen some evolution and is often a source of concern.
Strict Legal Requirements: Telegram has updated its Privacy Policy (as of September 2024, according to search results) to state that it may disclose your IP address and phone number to relevant authorities in response to a valid legal request.