MQTT is the de-facto standard protocol for IoT use cases.
If you are interested in learning more, this category is here to provide a forum for:

This category can be used for all discussions around HiveMQ Cloud.

This category is the right place to ask any question regarding pre-built HiveMQ extensions from the HiveMQ Marketplace.

This category provides a space for all discussion and questions regarding the HiveMQ MQTT Broker Community edition.

This category is meant for HiveMQ customers and people evaluating the commercial HiveMQ offerings, HiveMQ Professional/Enterprise Edition and the HiveMQ Enterprise Extensions.

This category provides a space for all discussion and questions regarding the HiveMQ MQTT Client Library.

This category provides a space for all discussion and questions regarding the HiveMQ Extension SDK.

This category is meant to provide a space to discuss anything regarding the newly released MQTT Command Line Interface, which is based on the HiveMQ MQTT Client Library.
You can find the MQTT CLI on GitHub