I am currently using Home Assistant MQTT publish service from this the link below
Link: https://developers.home-assistant.io/docs/en/external_api_rest.html

The URL is: https:///api/services/mqtt/publish?={password/token}

It is running smoothly but I am just unsure how I can use IFTTT webhook POST to post a MQTT packet to the URL typed above and it is being received by my broker (which is also on the same device as my home assistant) since HTTP and MQTT is of different protocols. And since this does works how do I implement this?