I need some guidelines here. I am creating an online booking system for my client that interfaces with QuickBooks on their internal network (desktop QuickBooks, not online).
Do I need to go the full "publish app" route? I do not wish to sell this app in the marketplace. This is merely a custom booking system designed and paid for by the client. It seems like I need to "publish" the app in the marketplace for them to be able to use it.
Are there ways around this?
Update 06/23/2015 - To connect to a desktop QuickBooks installation the SDK with the Web Connector is now the only recommended approach. Intuit is removing Intuit Partner Platform (IPP) integration to desktop QuickBooks.
For the SDK/Web Connector, you don't need to go through any publication process or anything like that. Just build the solution, and connector your client.
There's a pretty good overview of how the QuickBooks web connector works on our QuickBooks wiki.
The QuickBooks SDK download also includes a huge PDF with detailed documentation about how to implement SDK/Web Connector applications as well.