20. Twitch Notifications


Design a notification service to send push notifications to subscribers whenever a streamer goes live on Twitch

Functional Requirements
  • Users should be able to subscribe to receive push notifications
  • Users should receive notifications to their mobile devices when a streamer goes live
Nonfunctional Requirements
  • P99 latency for notification delivery < 60 seconds
  • Fault Tolerant
  • High availability
  • Streamers only go live once a day at most
  • Users have no limit to the amount of notifications they can receive
Estimated Usage
  • 100,000 streamers
  • 1.5 billion users
  • Top 5% of streamers account for 90% of notifications sent
  • Streamers subscription count ranges from 0 to 20 million
  • 3 billion push notifications sent per day

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