Telegram's 5 Data Centers: DC2 Users Exist, DC3 Likely Empty
Original: Mysteries of Telegram Data Centers
Why This Matters
Clarifies infrastructure architecture for developers building on Telegram's MTProto protocol.
Telegram operates 5 data centers (DC1–DC5) across Miami, Amsterdam, and Singapore. Contrary to community belief, DC2 holds many users (e.g., German +49 numbers), while DC3 appears to have no active users since around 2020, when its users were likely migrated to DC1.
Telegram officially maintains 5 data centers: DC1 and DC3 in Miami, DC2 and DC4 in Amsterdam, and DC5 in Singapore. Each account is permanently tied to one DC at registration, determined by the phone number's country code. Users cannot switch DCs manually.
DC5 is notorious in the Chinese Telegram community for frequent outages, affecting users who registered with +86 numbers. A community bot designed to detect which DC a user belongs to found 360 users on DC1, 390 on DC5, 50 on DC4, and zero on DC2 or DC3—leading many to assume DC2 and DC3 were unused or subordinate servers.
However, this conclusion was incorrect. The bot's detection method was flawed. In reality, DC1, DC2, DC4, and DC5 all actively accept new registrations based on country code. DC2, for example, serves German (+49) and other European numbers. DC3, while still operational, likely had its users migrated to DC1 around 2020 and no longer accepts new registrations.
The article explains that proper DC detection requires using Telegram's MTProto protocol directly. Connecting to DC1 and calling the auth.sendCode API with a DC2-eligible number returns a PHONE_MIGRATE_2 error, correctly identifying the account's assigned DC. This method works regardless of which DC the client initially connects to.