# HiveMQ Extension for Kafka Customization

**URL:** https://community.hivemq.com/c/hivemq-extension-sdk/kafka-customization/14.md

[Latest](https://community.hivemq.com/latest.md) · [Categories](https://community.hivemq.com/categories.md)

---

## [About the HiveMQ Extension for Kafka Customization category](https://community.hivemq.com/t/about-the-hivemq-extension-for-kafka-customization-category/295)

<div class="topic-metadata">

**Author:** [@hivemq-support](https://community.hivemq.com/u/hivemq-support)\
**Replies:** 0

</div>

---

## [Serialization of message payload (confluent avro format)](https://community.hivemq.com/t/serialization-of-message-payload-confluent-avro-format/2895)

<div class="topic-metadata">

**Author:** [@Safina](https://community.hivemq.com/u/Safina)\
**Replies:** 1\
**Last updated:** [May 29, 2024, 3:47pm UTC](https://community.hivemq.com/t/serialization-of-message-payload-confluent-avro-format/2895 "2024-05-29T15:47:52Z")

</div>

Hi, I am integrating HiveMQ with Confluent cloud and writing a confluent flink sql queries on messages ingested into Kafka topics. After researching found that HiveMQ sends key as topic name and value as payload. Hence…

---

## [HiveMQ MQTT-To-Kafka key](https://community.hivemq.com/t/hivemq-mqtt-to-kafka-key/2729)

<div class="topic-metadata">

**Author:** [@mhx](https://community.hivemq.com/u/mhx)\
**Replies:** 1\
**Last updated:** [February 23, 2024, 3:46pm UTC](https://community.hivemq.com/t/hivemq-mqtt-to-kafka-key/2729 "2024-02-23T15:46:51Z")

</div>

Hi, How do I set the key of the a kafka record in a mqtt-to-kafka-mapping in the configuration file? I want to set the mqtt-clientid as the key in the target kafka records.