Pivotal Event

A domain event that marks the boundary between two parts of the system, often where one team hands work over to another. The natural seam to split a flow into bounded contexts.

A pivotal event is a domain event that marks a clear boundary between two parts of the system, usually the moment when one team's responsibility ends and another's begins. "Order Delivered" is the classic example: everything before it is the orders flow, everything after it is settlements, billing, and payouts.

You spot pivotal events during Big Picture Event Storming. After laying out the events on the timeline, the team draws a vertical line over an event that clearly separates two clusters of sticky notes. This is often a moment of handover, when the story marked by events changes character.

Splitting the system at a pivotal event often aligns well with bounded contexts and team boundaries. The upstream team owns the events leading up to it, and the downstream team owns the parts that react to it. Each side can evolve independently as long as the contract is respected.

If you're designing a flow and you can't tell where the natural break is, run a Big Picture session. Finding pivotal events can help you discover the boundaries.