Problem context and objectives
Lead systems engineer · Draw the High-Level Map
Create the HLD for a co-op quest service that stores progress, grants rewards, and updates a social activity feed without making one request depend on every subsystem.
The design must survive players 2M concurrent and progress 80K updates/s. Every box must earn its place by satisfying a requirement or containing a failure.
How you win
- 1Trace one user action from request to durable outcome
- 2Connect every component to a stated requirement
- 3Explain the losing tradeoff, not only the chosen technology
Rules and pressure
- players: 2M concurrent
- progress: 80K updates/s
- Durable quest progress
- Reward exactly once
Live architecture trace
Draw the High-Level Map: request to outcome
Game client sends “progress command” to API gateway. Choose boundaries around cohesive responsibilities, data ownership, independent scaling, security, and failure isolation. Start simple; distribution adds cost.
Create the HLD for a co-op quest service that stores progress, grants rewards, and updates a social activity feed without making one request depend on every subsystem. Follow one real user action through the complete architecture; a component is useful only when you can explain the request, state, or failure it handles.