Would it be possible to change the button_type (one of momentary, toggle, detached or action) using the API?
I need it for my Shelly 2.5 in roller mode (https://shelly-api-docs.shelly.cloud/#shelly2-5-settings-roller-index) to stop my little one from switching in.
Hi and welcome to the forum. 
It's documented, so it should be possible. 
I'm actually a developer but I don't understand the documentation. Retrieving via GET is easy and quickly done, but how do I change? A POST or PUT request won't work and a GET with the params in the URL doesn't either (as the documentation states "as application/x-www-form-urlencoded POST payload").
What's the correct syntax for a change?
http://192.168.xxx.xx/settings/light/0?btn_type=detachedwas for a dimmer for you it is relay instead of light
that works, thanks a lot