As with all other transports, the translation between EPL events and MQTT payloads is based on the choice of host plug-in and codecs. See Host plug-ins and configuration and Codec Connectivity Plug-ins for further information.

The payload for the MQTT message is a byte array. Therefore, the String codec should usually be used to convert a byte[] (Java) or buffer_t (C++) type payload into a hostward string event. The same String codec can also be used to convert a string event to a transportward message with a byte[] or buffer_t type.