Let's Control It

It is possible to read data from FHEM server and display them on the OLED screen? What is the syntax?
I would like to show other temperature sensors or states other devices.
I know that FHEM includes HTTP API, but I never used it.
I could use a little help

You could write a ESPEasy plugin to read data from FHEM. If you do not want to do that then you have to go the other way and use FHEM to send data to your display. You can do this with the generic MQTT module or with the more comfortable ESPEasy module.