Example Kafka Event

{
  "order_id": "ORD-20250927-123",
  "event_type": "ORDER_CREATED",
  "payload": {
    "customer_id": 789,
    "total": 149.95,
    "items": [
      { "product_id": 10, "qty": 2 },
      { "product_id": 20, "qty": 1 }
    ]
  },
  "created_at": "2025-09-27T13:10:00Z"
}

• Clean JSON event ready for consumers.
• Can be routed to multiple topics or services.

Benefits of the Outbox Pattern with Debezium

• Consistency → business data and events always match.
• No dual writes → only one transaction.
• Flexibility → same event can be consumed by many services.
• Replay → Kafka keeps events for later reprocessing.
• Scalable → works with many consumers without changing the database.

Best Practices

• Partition Kafka topic by the right key (e.g., order_id or customer_id).
• Use Debezium’s unwrap transform for clean events.
• Monitor with heartbeat to ensure Debezium is alive.
• Use dead letter queue for error handling.
• Keep the outbox table small by cleaning up old records.

Conclusion

The Outbox Pattern is the safest way to publish database changes as events.
With Debezium and Kafka:

• The app writes once to the database.
• Debezium captures the outbox record.
• Kafka distributes the event reliably to all consumers.

This pattern avoids dual-write bugs and makes your system truly event-driven and consistent.