http toggle command for a i3

I'm an happy user of a shelly i3. I'd like now to send to the i3 an http command to trigger (something like http://<url>/relay/0?turn=toggle for shelly 1) a button press on, let's say, the first button. Is it possible? Which is the syntax?

thgoebel and @Wilfrieduc thanks a lot for your prompt replies. I also went through the TD in German pointed out by Wilfrieduc but google translator is not that good and I had no success altough I fell that the TD gives answer close to what I'm looking for