The DC3 gap is interesting. I wonder whether they deprecated it because the other EU server had plenty of capacity, or still keep it but only for... "special" account data flow.
DC2 is the first connection point of all MTProto clients.
Any DC may refuse a request and force the client to switch DC.
Profile URL doesn't show where messages/chats/channels are stored, as telegram has two dedicated DCs mostly for media. The rest DCs allow media with bandwidth being throttled.
They claim that they store user data on different servers in different jurisdictions so it becomes more difficult for authorities to gain access [1]. Maybe that's true and it has something to do with these DCs that seem to be unused.
They do not claim that. They do claim that they store specifically encryption keys in several data centers in different jurisdictions. Here is the exact quote: "All data is stored heavily encrypted and the encryption keys in each case are stored in several other data centers in different jurisdictions". So only keys are distributed.
It's more about the fact that five eyes intelligence services prefer to officially spy on each other's countries so they don't have to answer to their respective bureaucrats. They prefer plausible deniability.
Something like this:
DC1 politically belongs to UK which "spies" on CA/US but physical servers are located in US so US ultimately retains control.
DC2 politically belongs to France which "spies" on RUS/UKR/DE but physical servers are located in NL (e.g. in UK because one wouldn't be able to spot difference in ping). Maybe it's politically owned by UK/NZ or UK/AUS because France can't be publicly caught spying on Germany. But France wouldn't risk public arrest of Telegram CEO and the spectacle with russia if there is nothing to gain.
DC4 politically belongs to USA which "spies" on UK/Israel but physical servers are in NL/UK
DC5 politically belongs to UK/USA which "spies" on AUS/China/India but physical servers are in Singapore (e.g. former UK colony)
I love mentioning the UK in these kind of discussions because the pushback is biggest every time the Crown is mentioned, and ultimately US/CA/NZ/AUS are all colonies under the King.
Really cool to see realpolitik mapped out like this. It also highlights the problem of metadata with these kind of topics.
It makes sense: European users are assigned to EU data center, and Chinese to the one closer to them. The "custom code" should not be complicated, just a map of country to DC.
You are suggesting to develop a compicated solution (spend money) when current simple one is working ok without any elections.
If you've ever actually tried to implement server clustering you quickly find there's no magic cloud, except in specific cases like blockchains. A privately operated cluster system is mostly about directing requests to the correct server out of a finite set of servers.
DC in Miami, explains why Telegram app is snappy fast for me. I notice similar speed improvement with Meta and other big tech apps when I'm on the west coast. I guess latency matters when your app is making tons of requests.
Most of big tech's major data centers are in Loudoun County, VA on the east coast not the west coast. It's centrally located to be great latency for the east coast and OK latency for west coast and Europe. Plus a friendly regulatory environment and lots of existing DCs (AWS us-east-1, Azure East US 1/2)
If you're feeling any better latency on the west coast it's more likely to be placebo than real.
idk, they probably tried to get people on DC's as close to their location as possible. Using your phone number's country code might seem like a good way to do this at first, and they probably didn't give it much more thought before building the whole thing on this idea.
Beautiful analysis. It really looks like the country distribution [1] follows the geographical split between five eyes intelligence services, and maybe a small slice for France after they imprisoned the Telegram CEO [2] in order to take over data ownership from russia.
The Lex Fridman podcast episode with Pavel Durov is worth listening to. Their servers are built to be very secure — of course, it would be different for others, and they use some clever tricks
Good story, I yet believe the guy is trying to do the right thing. In the lex Friedman podcast he talks about banning extremist channels in both sides always, the story focus more on the Nalvani's block, but accordingly him he also bans other sides depending on the content.
I do follow a number of Telegram channels about the Ukraine war, and the pro Ukraine channels are there together with pro Russian channels.
The DC3 gap is interesting. I wonder whether they deprecated it because the other EU server had plenty of capacity, or still keep it but only for... "special" account data flow.
Also, it looks like it's easy enough to ID your DC on their API, though I haven't tried it yet (more of a Matrix Stan personally): https://core.telegram.org/method/help.getConfig
The article is from May 2022, just fyi.
I think it was reposted today because https://core.telegram.org/bots/serverless was just announced, which prompted some curiosity on HN about Telegram's architecture (https://news.ycombinator.com/item?id=48918534). But yes, the title should be updated to indicate this.
DC2 is the first connection point of all MTProto clients.
Any DC may refuse a request and force the client to switch DC.
Profile URL doesn't show where messages/chats/channels are stored, as telegram has two dedicated DCs mostly for media. The rest DCs allow media with bandwidth being throttled.
They claim that they store user data on different servers in different jurisdictions so it becomes more difficult for authorities to gain access [1]. Maybe that's true and it has something to do with these DCs that seem to be unused.
[1] - https://telegram.org/privacy
They do not claim that. They do claim that they store specifically encryption keys in several data centers in different jurisdictions. Here is the exact quote: "All data is stored heavily encrypted and the encryption keys in each case are stored in several other data centers in different jurisdictions". So only keys are distributed.
It's more about the fact that five eyes intelligence services prefer to officially spy on each other's countries so they don't have to answer to their respective bureaucrats. They prefer plausible deniability.
Something like this:
I love mentioning the UK in these kind of discussions because the pushback is biggest every time the Crown is mentioned, and ultimately US/CA/NZ/AUS are all colonies under the King.Really cool to see realpolitik mapped out like this. It also highlights the problem of metadata with these kind of topics.
This strikes me as a huge amount of custom code and technical debt. Every new software dev probably has to learn this.
Why not a sticky master election per user, and have no special data centers?
It makes sense: European users are assigned to EU data center, and Chinese to the one closer to them. The "custom code" should not be complicated, just a map of country to DC.
You are suggesting to develop a compicated solution (spend money) when current simple one is working ok without any elections.
From what I have read, they only have ~30 employees. They're not exactly onboarding a lot of new people here.
If you've ever actually tried to implement server clustering you quickly find there's no magic cloud, except in specific cases like blockchains. A privately operated cluster system is mostly about directing requests to the correct server out of a finite set of servers.
Learn what? How to count to 5?
DC in Miami, explains why Telegram app is snappy fast for me. I notice similar speed improvement with Meta and other big tech apps when I'm on the west coast. I guess latency matters when your app is making tons of requests.
Most of big tech's major data centers are in Loudoun County, VA on the east coast not the west coast. It's centrally located to be great latency for the east coast and OK latency for west coast and Europe. Plus a friendly regulatory environment and lots of existing DCs (AWS us-east-1, Azure East US 1/2)
If you're feeling any better latency on the west coast it's more likely to be placebo than real.
On the contrary, Big tech famously has plenty of data centers on the west coast:
• Quincy, WA (Microsoft)
• The Dalles, Oregon (Google)
• Prineville, Oregon (Facebook, Apple)
• Hillsboro, Oregon (Cloudflare, others)
• Boardman, Oregon (AWS)
By traffic load east coast datacenters dwarfs these.
I'm on DC5 since I lived in Korea when signing up, but I cannot say I've noticed many outages.
https://archive.is/VHlJH
i'm far from an authority on content delivery or whatever, but the first thing I thought of was what a bizarre way to setup your infrastructure!
idk, they probably tried to get people on DC's as close to their location as possible. Using your phone number's country code might seem like a good way to do this at first, and they probably didn't give it much more thought before building the whole thing on this idea.
Beautiful analysis. It really looks like the country distribution [1] follows the geographical split between five eyes intelligence services, and maybe a small slice for France after they imprisoned the Telegram CEO [2] in order to take over data ownership from russia.
[1] https://dev.moe/wp-content/uploads/2022/05/image-14.png
[2] https://en.wikipedia.org/wiki/Arrest_and_indictment_of_Pavel...
something smells suspicious about this kind of data routing
The Lex Fridman podcast episode with Pavel Durov is worth listening to. Their servers are built to be very secure — of course, it would be different for others, and they use some clever tricks
More mysteries of Telegram Data Centres: https://istories.media/en/stories/2025/06/10/telegram-fsb/
(and a follow-up: https://istories.media/en/news/2025/06/10/telegram-responds-... )
Good story, I yet believe the guy is trying to do the right thing. In the lex Friedman podcast he talks about banning extremist channels in both sides always, the story focus more on the Nalvani's block, but accordingly him he also bans other sides depending on the content. I do follow a number of Telegram channels about the Ukraine war, and the pro Ukraine channels are there together with pro Russian channels.
It's a great an telling investigation. Dropped in to share it as well. Telegram deserves no trust from us.