Sensor Value out of Homeassistant

I need to have a single sensor value exposed to an external app. possibly in a secure way.
Is there a simple way to do it?
I know about tasker mqtt integration but I am looking for an easier way (one way homeasssistant ->tasker) to get a value.

Ok I think I got it

GET /api/states/<entity_id>

ICould someone give me an example?