What is the Outbox Pattern?

A microservices pattern that ensures reliable message delivery in distributed systems, solving the dual-write problem.

When a service needs to update its database and publish an event to a message broker (e.g., Kafka), a crash in between causes data inconsistency. The Outbox pattern solves this by writing the domain entity and the event to an 'Outbox' table in the same local database transaction. A separate process relays the Outbox table to the broker.