QuickBooks's Webhooks support has arrived!
Just when you thought they were never going to actually do it ‐ they did it. I have a full tutorial on getting started using the qbo_api gem but the information is very applicable for quickbooks-ruby as well.
Non-US invoices are pretty similar so take a look at this thread to get an idea on what needs to be done for a non-US invoice API request.
Not that easy. Remember QBD and QBO and not nearly that close with respect to feature parity as conventional wisdom would have it.
My last two QuickBooks consulting gigs have been MVPs so I am now offering that service. Please spread the word or refer me to a new project you may know of.