Data engineering·Moving data out of the source
the event carries the whole customer record rather than just an id, so the consumer never has to call back and ask.
Event-carried state transfer
Also calledstate-carrying event, fat event
Publishing enough state inside each event that consumers can maintain their own copy without querying the producer. It removes the runtime coupling of a callback and makes replay meaningful, because the history contains the values and not just the pointers. The trade is size, staleness semantics and versioning: every consumer is now parsing your schema, so the payload is a contract in a way that an id was not.