Event-Driven Notification Platform

Problem

Product teams needed reliable outbound notifications across channels without tight coupling between business logic and delivery providers.

Architecture approach

Event-driven routing: producers emit domain events; channel-specific consumers handle delivery, retries, and provider webhooks independently.

Key challenges

• Provider rate limits and template compliance (WhatsApp Business API)
• Delivery status reconciliation across async webhooks
• Poison messages and dead-letter recovery

Scalability decisions

• Partitioned queues by channel and tenant
• Outbox pattern for transactional event publish
• Dedicated retry tiers with exponential backoff

Outcome

Stable daily throughput with observable delivery funnels — new channels added by shipping consumers, not rewriting core flows.

Tech stack