OT: Quickbooks API

Hi all,

Sorry for the OT.
Has anyone used quickbooks api extensively? Just as any other api, as its consumer, it seems fairly easy, upon a quick glance over its documentation page, I didn’t seem to see an area about how to be such an api provider, that is, to create end points for other parties to consume, any insight? In addition, curious to know if there’s any testing site that allows such api consumption.