Third-party compilations: Databases that link phone numbers to Telegram User IDs are typically compiled by malicious actors who abuse Telegram's legitimate "contact sync" feature (by importing massive lists of numbers to see who's on Telegram) or from previous data breaches of other services, not from Telegram's core systems.
Publicly shared numbers: In some cases, users or groups explicitly post phone numbers in public Telegram profiles or group descriptions, making them publicly visible. This is a user choice, not a leak from Telegram's database.
Misconception 2: "When I join Telegram, my phone number is automatically visible to everyone."
Reality: This is incorrect. Telegram provides granular privacy controls over your phone number visibility. By default (or upon setup), you're prompted to choose. You can explicitly set "Who can see my phone number?" to "Nobody" in your Settings > Privacy and Security > Phone Number. If set to "Nobody," your number will never be displayed on your profile.
Misconception 3: "Syncing my pho ne contacts uploads my entire address book, making all my friends' data public."
Reality: This is a partial truth with a significant misunderstanding of "public."
What's uploaded: If you enable "Sync Contacts," Telegram telegram number database uploads only the phone numbers and the names you've assigned to them in your device's address book to its secure cloud servers. It does not upload emails, addresses, notes, or other details from your contacts.
Purpose: This is solely to identify which of your contacts are already on Telegram, allowing the app to populate your in-app contact list and notify you when a contact joins.
Privacy: This data is not made public. It's used internally by Telegram to provide the service. You can disable this syncing at any time and even "Delete Synced Contacts" from Telegram's servers.
Misconception 4: "If my phone number appears in a 'Telegram leak' database, it means Telegram was hacked."