Hi guys.
I’m the CCO of Icelandic start-up called Treble. We are creating cutting edge wave-based sound simulation for the AEC industry. We are creating plug-in’s to various BIM software to design and analyze acoustics. See more at www.treble.tech.
We need info regarding extension development and as well as regarding the online geometry editor. It would be greatly appreciated if someone in the community or an employee of Trimble could point me in the right direction 
Kind regards,
Gunnar
Everything you should need is right here on this page: https://developer.sketchup.com/
The web edition does not yet have an API.
As mentioned, the web version of SketchUp doesn’t have an API at this point.
In general our resources can be found from the Developer Portal: https://developer.sketchup.com/
Only the desktop application supports extensions. The documentation can be found here:
We also have resources on our GitHub channel: SketchUp · GitHub
There you will find examples, tutorials and developer tools.