HomeBrowseLearnFundamentally strongSoftware engineerTechnical communicationLearning Overview Beginner Scenarios Intermediate Scenarios Advanced Scenarios Capstone Overview RFC: Preventing Duplicate Shipment Notifications ADR-0006: Idempotency Cache for the Notification Worker PR Description: Notification Worker Idempotency Cache Postmortem: Duplicate Shipment Notifications Context Diagram: Notification Worker (C4 Level 1) Last updated July 15, 2026