Design a Spotify-like service. Listeners browse catalogs and playlists and stream audio files. Every play produces an event that must be counted for royalties and personalization, without slowing playback.

02 · Define success

Requirements

Serve track, album and playlist metadata with low latency.
Deliver audio files from storage close to listeners.
Record every play event durably for royalties and analytics.
Keep playback working when the analytics pipeline lags.

Open the design canvas Read the analysis first

Design envelope

20,000
peak reads / s: 2,000
writes / s: 200 ms
target read p99: 300 B
record size

Workload assumptions for this exercise, not measured production limits.

Think about request flow, durable state, hot paths and failure boundaries.

How this problem works

Design — place components and connect them on the canvas, then write your contracts.
Decide — pick the policies you would defend and note the trade-offs.
Review — run the rule-based review. Pass every check to complete the problem and add it to your review deck.

The review checks a guided model. Other valid architectures exist; it does not execute code or prove production readiness.

01 · Understand the problem

Your mission