Hello,
There is a HTTP POST receiver that publishes the value as a MQTT message. But this is only usable if you control the body format from the sender. Documented in the API-Doc. If the format can not be specified some software need to translate the data into our "IoT Open" format as you are now doing in NodeRED.
Are you trying to integrate a system into the platform? Most software suits can have MQTT as a protocol as well since that is fairly lightweight and that is the easiest way to get new values into the platform.
