Telling Volumio to change track or volume outside web page?

I’m in the process of getting Volumio working on my RPi3, controlled via my car’s OEM infotainment system.
I believe the touchscreen will work fine as the infotainment system’s built-in touchscreen runs a browser in kiosk mode.

However, I also want to make use of the various physical knobs in my car to control the track navigation and volume. I can intercept the events of knob movement from the car’s infotainment framework. I think translating that into a touch on the touchscreen may be difficult. Is there any way to tell Volumio to navigate track and modify volume outside of the web page (and have the display updated in the web page once done)?

Yes you can, using either GPIO (the plugin) or websocket API (or event REST, but they are not very comprehensive yet…)

I have Volumio version 2.041. Per other comments I found on here, recent builds have Rest API.

I tried launching a 2nd browser, pointing it to URL VolumioIP:3000/api/v1/commands/play and it appears to redirect the browser to the main playback front-end without actually starting to play the song that’s loaded.

Any advice?

I downloaded and copied to my car infotainment system. The emit method is working!