Waterstream is an MQTT broker that runs Kafka natively as a Kafka Streams application. There are no external MQTT clusters to manage or integration pipelines to develop to move your data from devices to topics because Waterstream works a bidirectional layer between Kafka and IoT devices.
Waterstream does not require an intermediate persistence because it uses Kafka as the only persistence layer under the hood with all its benefits like high availability, high throughput, and low latency. Messages coming from MQTT clients are immediately written to Kafka and vice versa: as soon as the message is retrieved from Kafka, it's sent to MQTT clients.
Also, the MQTT state is stored in Kafka with no need for additional storage solutions. Waterstream runs on top of Kafka.

More details here: https://waterstream.io/