So can a RDBMS... But that doesn&#x27;t mean that Kafka and databases are related.<p>As multiple comments have stated above, Kafka is really a distributed message subsystem. Its core interface is a set of topics that one can publish to, and that consumers can read from (in other words, a pub-sub system). Kafka doesn&#x27;t inspect the message payload at all.<p>Elasticsearch is a unstructured (to some extent) document store that&#x27;s optimized around document <i>search</i>. So at the very least, the payload is important when using Elasticsearch.