Published onJuly 7, 2026Exactly-Once Kafka Processing with Spring Boot and PostgreSQL: Outbox and Idempotent ConsumersApache-KafkaSpring-BootPostgreSQLTransactional-OutboxIdempotencyEvent-Driven-ArchitectureLearn where Kafka exactly-once semantics stop, why database side effects still need idempotency, and how to combine a PostgreSQL outbox with an idempotent Spring Kafka consumer.