Microservices Design Service Boundaries Define services around business capabilities, not technical layers. Each service owns its data store and exposes a clear API contract. Event-Driven Communication Use idempotency keys ( ) to handle duplicate deliveries safely. Saga Pattern (Orchestration) API Gateway Pattern Health Check Pattern Anti-Patterns - Sharing a database between services (tight coupling) - Synchronous HTTP chains across multiple services (cascading failures) - Building a distributed monolith (services cannot deploy independently) - Missing circuit breakers on inter-service calls…