ABOUT THIS EPISODE
In this "Build Along" episode, we move from theoretical patterns to practical implementation. We are designing a Real-Time Notification System—the kind of engine that powers apps like Uber, Twitter, or Slack.
The challenge isn't just sending a message; it's doing it for millions of users simultaneously across different channels without losing data. We architect the system from the ground up:
The Ingestion Layer: Handling massive spikes in traffic using message queues like Kafka or RabbitMQ.
The Dispatcher: How to manage different delivery providers (Firebase for Push, SendGrid for Email, Twilio for SMS) and handle their varying rate limits.
State Management: Tracking whether a notification was "Sent," "Delivered," or "Read" in real-time.
User Preferences: Implementing a "Fan-out" pattern that respects user-defined quiet hours and channel preferences.
