I working on an solution for SharePoint Online, and would like to be able to not have a virtual machine for developing the NCSS parts of the project. But with the Visual Studio template I would have to work offline and do a publish to see the results. Are there some extensions for Visual Studio to be able to work with sandbox solutions without having to install SharePoint?
If you create a string value named "SharePoint" set to "Installed" under the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\15.0 you will be able to create sandbox solutions without having SharePoint installed. (You'll also need to install Office Developer tools for Visual Studio)
You will still need to publish the solutions and upload to SharePoint Online in order to test.