Salesforce·Software Engineer·Onsite - System Design / Architecture
- Design a Watch Party system where a host creates a virtual room with a unique ID, multiple users can join, and everyone's video playback stays in sync in real time. Support play, pause, seek, and playback speed controls.
- How does a playback control command from the host propagate to all participants given variable network latency and client clock drift?
- Walk through the edge cases: a participant joining mid-playback, the host disconnecting, conflicting near-simultaneous commands, a buffering client, and a participant who drops and reconnects.
- How would you scale this to hundreds of thousands of concurrent rooms across multiple servers, and how do you handle failover for a room's authoritative node?
- If any participant could issue playback commands instead of just the host, how would you prevent control conflicts and ensure a deterministic command ordering?
- How would you measure sync quality in production and alert when participants in a room are drifting apart?
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