This app has some decent potential but the google connection aspect needs to be revisited. After connecting, the app verifies as much and when using a template, could write new spreadsheets to my account. When I tried to connect to an existing sheet, however, I could never get it to work. I disabled pop-ups, allowed 3rd party cookies for all sites, added specific permission for the Chartmat app and google, added wildcard permissions for both domains AND tried all of this in 3 different browsers. I was never able to use an existing sheet. Good concept in theory.