Klaviyo Reference Architecture Overview Production-ready architecture for Klaviyo integrations: layered project structure, service patterns, event-driven sync, and the SDK wired into a real application. Prerequisites - TypeScript project with installed - Understanding of layered architecture - Redis (for caching/queuing) and database (for audit/sync state) Project Structure Layer Architecture Rules: - API layer calls Service layer only - Service layer calls SDK layer and Infrastructure - SDK layer never calls upward - Webhooks are treated as API endpoints Instructions Step 1: Config Layer Ste…