Design TikTok / Reels
Last Updated: December 25, 2025
What is TikTok/Reels?
TikTok (and Instagram Reels, YouTube Shorts) are short-form video platforms that allow users to create, share, and discover videos typically ranging from 15 seconds to 3 minutes in length.
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The core experience revolves around an algorithmically-curated "For You" feed that surfaces personalized video content based on user behavior, interests, and engagement patterns.
Users can scroll through an endless stream of videos, interact with content through likes, comments, and shares, and create their own videos with built-in editing tools.
In this chapter, we will explore the high-level design of a TikTok/Reels-like short video platform.
This problem tests your ability to design for massive scale, handle video processing pipelines, build recommendation systems, and optimize content delivery globally.
Let's start by clarifying the requirements: