How do applications connect to QuickBooks?

Somebody asked me a question over the weekend that I haven't really thought about in a while. I was discussing OE Companion with the owner of one of the companies that is helping in our alpha tests. He asked how applications are able to exchange data with QuickBooks and/or QuickBooks Online. Here is my answer.

QuickBooks provides a software development kit (SDK) that is free and open to anyone who is interested. This QuickBooks SDK provides all the information that is needed to exchange data with QuickBooks. It is basically a series of requests and responses in a specific format. If an application needs a list of all customers in QuickBooks, the app has to make that request in a format understood by QuickBoooks. Then the response will be sent in a specific format as well. Here is a specific example. Let's say that I include the following tag in a request to QBOE:

<CompanyQueryRq />

The response will come back with information about the QuickBooks Online company - address, phone number, etc. That's it. You have exchanged information with QuickBooks. There is obviously a lot more going on behind the scenes in any data exchange. But at the core, that is it. Please leave comments if you have any questions. Have a great week!