A trigger for "REST API received a POST request"

I have a computer (say A) physically close to a sensortag (v2) device. It runs a python program that communicates to the sensortag via bluetooth, and sends the measurement updates to another computer (say B) running home assistant via the REST API of home assistant. Such updates usually change the state of some entity in home assistant (on B), but not always – the new measurement may be the same as the old value. Currently, I use the “state-changed” trigger, but that doesn’t work in my application. I need the automation to trigger every time a POST request is received for the state of a particular entity. The automation feeds the measurements to a radio thermostat. The thermostat freaks out if it doesn’t get a fresh value of the temperature sensor for too long.