TikTok's server architecture is based on cloud computing and distributed systems. TikTok's back-end server basically consists of three main parts: storage, computing and services.

Storage: TikTok needs large-scale storage to store videos, user information, comments, likes and other data uploaded by users. These data are usually stored in distributed storage systems, such as Object Storage or Distributed File System. This storage mode can provide high availability and scalability to deal with massive user data.

Computing: TikTok's back-end server needs to perform various computing tasks, including video encoding and decoding, video processing, content recommendation, user personalized recommendation, etc. These calculations are usually implemented by distributed computing frameworks (such as Hadoop, Spark, etc.), which can use a large number of server resources to process data and computing tasks in parallel.

Services: TikTok's back-end server needs to provide various services, including user authentication, video upload, video playback, message push, social functions, etc. These services are usually implemented by microservice architecture. Each service is responsible for a specific function and communicates through API interface.

TikTok will also use the content distribution network (CDN) to accelerate the transmission of video content and reduce the loading delay when users access video. CDN caches video content to server nodes distributed around the world, and users can quickly obtain video content from the nearest node, improving the user experience.