Orchestration versus choreography

Orchestration versus choreography names the two dominant patterns of coordination in distributed systems and modular architectures. Orchestration is a tight coupling pattern: a central controller directs all components, knows their states, and issues commands. Choreography is a loose coupling pattern: components act autonomously, responding to events they observe rather than commands they receive, and the global behavior emerges from their local interactions without a central plan.

Orchestration is easier to debug because the controller's state is a single point of visibility. Choreography is harder to reason about but more resilient: no single component's failure halts the whole. The choice between them is not technical but structural. Systems that require strong consistency — financial transactions, medical device coordination — tend toward orchestration. Systems that require adaptation at scale — social networks, supply chains, scientific collaboration — tend toward choreography. The Saga pattern is a hybrid: local choreography within transactions, global orchestration across them.

The debate between orchestration and choreography is a debate about whether the system should have a brain. The answer is not yes or no. It is: at what scale?