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Real-time systemsEasySDE-1

Your app keeps a WebSocket open for live updates. Product wants users to get a message even when the app is closed. How does that work, and how do the two delivery paths fit together?

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Think first

Answer out loud as you would in the room — clarify, give numbers, name the trade-off — then compare with the model answer.

Go deeper

Design a notification system (push, SMS, email) Lesson: Real-time at scale: WebSockets, SSE and presence

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