Hi QuickBooks developer,
I will have many small simple QuickBooks projects. You actually do not need to write QuickBooks add-ins. You only need to convert data from our format to IIF format of QuickBooks. We have sample code already. We also have sample data for different version of QuickBooks. However, users may need to add some more columns or remove some columns then you will need to read the structure of Quick Books IIF headers (Search on QuickBooks Help). You also need QuickBooks version 2007 and up in order to test data to import. If you have many QuicBooks version, it would be a plus.