Where Should a Transaction End? Designing Consistency Boundaries in Distributed Java Systems

Microservices do not eliminate transactions. They force architects to decide where a transaction should end.

That decision is harder than it sounds. A business operation that was once handled inside a single database transaction may cross several services after decomposition. An order can involve inventory, payment, pricing, customer limits, audit history, and notification. The architecture may divide these responsibilities cleanly, but the business still sees one operation: place the order.