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Problem Understanding
Restate the problem in your own words.
Design Spotify (Music Streaming)
Design a Spotify-class music streaming service: search a catalog of 100M+ tracks, build personal + collaborative playlists, stream encrypted audio segments via CDN, generate Discover Weekly / Daily Mix recommendations, and count plays accurately for royalty settlement. Stream-start latency under 500 ms is the headline UX bet; per-segment DRM keeps labels happy. The architecture is YouTube-for-audio plus a recommender that closes the loop in minutes — the differentiator is the recommender and the playlist UX, not the streaming bytes.
- Spotify~500M MAU. CDN-served encrypted audio + a two-tier recommender (online rerank + Discover Weekly batch).
- Apple Music100M+ tracks, deeply integrated with iCloud + the music store; lossless audio is a differentiator.
- YouTube MusicMusic surface on top of the YouTube CDN; same recommender substrate as YT itself.
- TidalHi-fi-first music streaming — lossless / Atmos masters; smaller catalog, audiophile audience.
Your task: read the problem above, then write what the system is, who uses it, the rough scale, and the headline UX expectation — in your own words. Submit for AI review when you're ready.
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