Design a multi-channel notification system

Q: Design a multi-channel notification system

This System Design question evaluates distributed-systems and API-design skills—scalability, reliable fanout, multi-channel integration, delivery guarantees (retries, idempotency, deduplication), rate-limiting, subscription/preferences modeling, and observability.

Q: How do I approach System Design interview questions?

System Design questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master system design interviews.

Question

Design a notification system that receives alert events from other internal systems and notifies all subscribed users through multiple channels (e.g., in-app/push, email, SMS).

Your design should address:

Core requirements and APIs (publish alert, manage subscriptions/preferences, send notifications)
Fanout to many subscribers
Multiple delivery channels with different providers
Reliability (retries, dead-letter queues), ordering/deduplication, and idempotency
Rate limiting and user preferences (opt-out, quiet hours)
Observability and operational concerns

Assume high volume (millions of alerts/day) and that different alert types may have different urgency and SLAs.

Design a multi-channel notification system

Quick Overview

Solution

Comments (0)