Orchestration vs. Choreography in a service based architecture

Orchestration and Choreography are required when multiple services must be coordinated to complete a certain business transaction.

Orchestration is the coordination of multiple services through the use of a separate mediator service that controls and manages the workflow of the transaction (like a conductor in an orchestra).

Choreography, on the other hand, is the coordination of multiple services by which each service talks to one another without the use of a central mediator (like dancers in a dance).

As services become more fine-grained, both orchestration and choreography are necessary to tie the services together to complete the business transaction.

Additional Resources: https://cloud.google.com/blog/topics/developers-practitioners/service-orchestration-google-cloud