CDC with Debezium

CDC publishes every row change in your Rails DB as a Kafka event. Downstream consumers (search index, data warehouse, audit log, downstream services) get them without your app emitting anything. Powerful and dangerous — every Rails write becomes a public contract.

The opinion

Use Debezium with Postgres logical replication when you have multiple downstream consumers needing eventually-consistent DB state (search, warehouse, cache invalidation). Do NOT use CDC as your domain event bus — emit explicit domain events from the app layer for that. CDC leaks schema; domain events express intent. Set REPLICA IDENTITY FULL on tables you publish from. Use a single publication and replication slot per Debezium connector. Tombstone-handle deletes.

When CDC fits