Picture a pizza shop with three stations: dough, oven and delivery. An order comes in. How does that pizza get from one station to the next?

In the first shop, a manager stands in the middle and calls out every step. In the second shop, there's no manager. A ticket goes up on the rail, and each station jumps in as soon as the one before it finishes.

Software teams face the same choice with microservices. The names are orchestration and choreography. Here's how to tell them apart, and when each one is the right call.

The shop with no manager (choreography)

Every station knows its own job and watches for its cue. Dough is ready, so the oven starts. The pizza comes out, so delivery picks it up. Nobody holds the whole plan. It only exists as the sum of everyone's reactions.

Most days, that's lovely. Then a customer calls: "Where's my pizza?" Nobody can say. You walk from station to station asking.

In software, services publish events to a message broker and react to each other's events.…