What counts as a single message?

For billing purposes, only PUBLISH MQTT packets, both incoming and outgoing, are counted. To best balance billing between customers we ‘normalize’ messages to a value of 5KB. For example, if you send an 8KB message, it will be counted as two normalized messages. The message’s topic, headers, and payload (and if using MQTT5, user properties) are all combined in this sizing calculation.

HiveMQ Cloud Starter plan uses the default expiry values, so 4,294,967,296 seconds for sessions and message expiry.

Only HiveMQ Cloud Serverless plan has a data retention policy of 3 days.