What is the difference between ProducerFactory and KafkaTemplate in Spring Kafka?

ProducerFactory creates KafkaProducer instances (the underlying Kafka client). By default it's a DefaultKafkaProducerFactory which may pool or create per-thread producers. KafkaTemplate is a higher-level abstraction that uses ProducerFactory to get a producer, sends messages, and handles futures. For transactional producers, ProducerFactory must have a transactionIdPrefix — it creates a new producer per transaction. In Spring Boot, both are autoconfigured. You typically only inject KafkaTemplate unless you need to customize producer lifecycle.

Expected key concepts: ProducerFactory, KafkaProducer, DefaultKafkaProducerFactory, KafkaTemplate, abstraction, transactionIdPrefix, autoconfigured, producer lifecycle, pool, per-thread