System design interview questionHardDistributed Architecture
Design a Music Streaming Service like Spotify
Design Spotify-style music streaming: catalog + playlists, and stream audio to many listeners via CDN — not live concert ingest.
Interview scope
Control: Client → Gateway/LB → App → Cache + DB. Audio: Client → CDN (+ Object Storage origin). No Client → DB for audio bytes.
Functional requirements
- Browse/search catalog and playlists.
- Stream audio tracks to authenticated listeners.
- Track play history / likes at a high level.
Scale and quality goals
- Audio bytes via CDN + Object Storage.
- Metadata/playlists are cache + DB friendly.
- Don’t serve global audio egress from one App Server.
Capacity assumption
Design for this scale
Assume ~100M streams/day (~1,160 stream-starts/s average) with heavy concurrent listening at peak.
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