In my Spring Boot microservices projects, Kafka is integrated in the service layer. After the business logic completes—for example, saving an order to the database—the service publishes an OrderCreatedEvent using KafkaTemplate. Other microservices, such as Inventory and Notification, consume the event using @KafkaListener with their own consumer groups. This asynchronous, event-driven approach decouples services, improves scalability, and allows independent deployment. In production, I would also configure retries, dead-letter topics (DLQs), appropriate partitioning, and idempotent producers to make the messaging reliable.