Information regarding OPERA Web Self Service (OWS), OPERA Exchange Interface (OXI), and OPERA HTNG Interface specifications can be publicly found at https://docs.oracle.com/en/industries/hospitality/?tab=2 under OPERA Integrations. It is important to note that the OPERA Cloud Authentication specifications MUST be completed for each integration type purposed to interface with the Oracle Cloud environment.
We need to be careful on the wording about who needs to validate and when. 3rd parties have no development rights to our software or APIs. Customers do have some rights to use the APIs, depending on what they've purchased, and may contract 3rd parties to build those integrations for them (specifically the customer), but have no rights to assign that IP. This is why we say that a site can build (or have someone build) an integration which is only for that client (a.k.a. "non-repeatable", "one-off", "client-specific", "non-sellable", etc.)
Partners who join OPN at the Gold level have the rights to develop against our API sets and resell their integrations to customers with our products. However, we require that they first submit an integration request so that we can review to make sure that their solution is supported by an existing API set. We require this because we've had a number of partners join OPN, then start to develop, only to realize that the APIs don't support something critical to what they want to do. Then they demand we add it asap, followed by a demand for an OPN refund (which is a difficult process requiring hard to obtain high-level approvals). It's all about due diligence before the fact.
If partners want to move forward and request an integration, they should submit the request to the HGBU Partner Integration Portal:
Rather than a stock answer, I think the best thing would be to refer questions to the published FAQ: