System design interview questionHardSocial / Media
Design a Short-Video Platform like TikTok
Design TikTok-style short video: upload clips, process them, and serve a For You feed with CDN playback.
Interview scope
Upload: Client → Gateway/LB → App → Object Storage + DB + Queue. Watch: Client → CDN. Feed: App → Cache + DB. No Client → DB for video bytes.
Functional requirements
- Upload a short video.
- Transcode/thumbnail asynchronously.
- Serve personalized feed + stream video via CDN.
Scale and quality goals
- Playback egress via CDN + Object Storage.
- Feed reads should hit Cache.
- Transcoding via Message Queue — not inside upload HTTP.
Capacity assumption
Design for this scale
Assume ~50M video views/day (~580 RPS average) with heavy mobile scrolling peaks.
Practice more than a diagram
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