Order Events for Five Teams

When an online shop confirms an order, five separate teams need to act on it: warehouse picking, invoicing, the loyalty points service, fraud analytics and customer emails. Today the order service calls each of them directly, so one team's outage makes checkout slow or fail. The shop wants the order service to announce each confirmed order exactly once and carry on, with every team receiving its own copy. A team that is down for maintenance must find its orders waiting when it comes back rather than lose them, a slow team must not hold up the others, and adding a sixth team later should not require changing the order service.