Inside ByteDance’s Massive Bandwidth: How Douyin Serves Hundreds of Millions

Recently a question arose about how Douyin’s servers can support so many simultaneous users, prompting a technical overview.

Douyin, Baidu, Alibaba Cloud, and Tencent each maintain T‑level outbound bandwidth (approximately 1 TB/s) and data centers with over 200 k servers.

ByteDance’s total data‑center bandwidth is estimated around 10 TB and is expected to surpass 15 TB soon.

In practice, a total outbound capacity of 1 TB often translates to individual rack bandwidth of about 100 G, achieved through dual‑ or multi‑link designs that aggregate to T‑level throughput.

Server count evolution: in 2017 ByteDance operated 20‑30 k rented servers; in 2018 it built its own data center in Hebei (Phase 1: 50 k servers, Phase 2: 90 k servers); by the end of 2018 the combined rented and owned fleet reached 170 k servers; recruitment data from 2020 indicates about 420 k servers.

In the United States, TikTok runs independently, renting roughly 100 k servers, and is also investing in data centers in India and Singapore.

The term “export bandwidth” essentially refers to the download capacity of a server farm. Small IDC providers may have only 5 G, while enterprises with substantial scale exceed 30 G.

Many enterprises now prefer cloud services such as Alibaba ECS, Tencent Cloud, Baidu Cloud, or AWS instead of building their own data centers.

A typical small corporate website might use 20 M bandwidth, 4 G RAM, and 100 G storage, costing roughly 4,000‑5,000 CNY per year.

Bandwidth remains a costly and scarce resource.

China Mobile’s data center in Shijiazhuang covers 174 mu (≈11.6 ha) with a 130,000 m² building, ten structures, 31 k racks, and 15 T of aggregate bandwidth.

Those 31 k racks can host up to 210‑360 k servers; using an average of 300 k servers yields a total outbound capacity of roughly 7‑10 TB. With dual‑exit and multi‑link designs, actual per‑link bandwidth of 800 G‑1 T can achieve about 10 TB of effective aggregate bandwidth.

Historical context: Shanghai’s total outbound bandwidth reached 1 TB only in 2009; a decade later, ByteDance’s data centers exceed that level.

CDN (Content Delivery Network) brings content to edge nodes close to users, reducing latency. Static pages are compressed and served quickly, often within 2 seconds. Dynamic video streams use intelligent routing, long‑connection protocols, and compression to optimize delivery.

For reference, Tencent’s CDN in 2015 supported 500 million daily active users, delivering up to 10 TB of bandwidth and handling trillions of requests per day.

In summary, ByteDance’s overall bandwidth is likely around 10 TB, enabling its suite of apps—Douyin, Xigua Video, Toutiao, Feishu—to serve hundreds of millions of daily active users smoothly.