Design a Multi-Channel Notification System
Company: Pinterest
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Online Assessment
Overview: Design a multi-channel notification platform for push, email, SMS, and in-app messages that respects consent, preferences, quiet hours, locale, priority, and frequency limits. Cover durable intents, idempotency, rendering, provider retries, deduplication, webhooks, fallback, auditability, and realistic delivery semantics.