Choreography vs orchestration patterns

In AWS development, choreography and orchestration are two fundamental patterns for coordinating distributed services and microservices. **Orchestration Pattern:** Orchestration uses a central coordinator (orchestrator) that controls the workflow and manages interactions between services. AWS Step… In AWS development, choreography and orchestration are two fundamental patterns for coordinating distributed services and microservices. **Orchestration Pattern:** Orchestration uses a central coordinator (orchestrator) that controls the workflow and manages interactions between services. AWS Step Functions is the primary orchestration service, acting as the central brain that defines the sequence of steps, handles error management, and maintains state. The orchestrator explicitly tells each service what to do and when. This pattern provides clear visibility into workflow progress, simplified error handling, and easier debugging. However, it creates a single point of control and can become a bottleneck. **Choreography Pattern:** Choreography is a decentralized approach where services communicate through events and react independently based on those events. Each service knows its responsibilities and responds to relevant events. Amazon EventBridge and Amazon SNS are commonly used for choreography in AWS. Services publish events when they complete tasks, and other services subscribe to these events to trigger their actions. This pattern offers loose coupling, better scalability, and greater flexibility for adding new services. **Key Differences:** - Control: Orchestration has centralized control; choreography is decentralized - Coupling: Orchestration creates tighter coupling; choreography promotes loose coupling - Visibility: Orchestration offers clearer workflow visibility; choreography requires distributed tracing - Complexity: Orchestration simplifies coordination logic; choreography distributes complexity across services **When to Use Each:** Choose orchestration (Step Functions) for complex business workflows requiring strict sequencing, comprehensive error handling, and clear audit trails. Choose choreography (EventBridge/SNS) when building highly scalable, loosely coupled systems where services need to evolve independently. Many AWS architectures combine both patterns, using orchestration for critical business processes while employing choreography for event-driven integrations between bounded contexts.