Design a Notification System System Design Interview

1. Problem Statement

2. Architecture Discussion Map

Use this as one discussion aid, not a single correct answer. Your design should follow from the requirements, scale, and trade-offs you establish.

graph LR
    A["Design a Notification System"]
    A --> F1["Decoupling Message Queues - Kafka/RabbitMQ"]
    A --> F2["Reliability & Retry Strategies Exponential Backoff, Dead Letter Queues"]
    A --> F3["Distributed Deduplication Idempotency keys via Redis"]
    A --> F4["User Preferences & Compliance Opt-in/Opt-out, GDPR"]
    A --> F5["Rate Limiting & Throttling Per-user vs Per-campaign"]
    A --> F6["Observability Tracing, Open Rates, Delivery Latency"]

3. Key Focus Areas

• 1
  Decoupling (Message Queues - Kafka/RabbitMQ)
• 2
  Reliability & Retry Strategies (Exponential Backoff, Dead Letter Queues)
• 3
  Distributed Deduplication (Idempotency keys via Redis)
• 4
  User Preferences & Compliance (Opt-in/Opt-out, GDPR)
• 5
  Rate Limiting & Throttling (Per-user vs Per-campaign)
• 6
  Observability (Tracing, Open Rates, Delivery Latency)