I'm wanting to implement and test Apple Pay on the Web using my localhost instance. I've managed to set everything up correctly and so I'm able to get a merchant session from the Apple Pay API, but the client code immediately calls oncancel after calling session.completeMerchantValidation. After following this I'm seeing the following in the terminal: com.apple.PassKit.PaymentAuthorizationUIExtension: (PassKitCore) [com.apple.passkit:Payment] Evaluating merchant session using PROD trust policy. com.apple.PassKit.PaymentAuthorizationUIExtension: (PassKitCore) [com.apple.passkit:Payment] Application failed to provide a valid merchant session. We can't proceed to authorize the transaction. From reading various online sources, including the documentation referenced above, it seems like this might be happening because localhost isn't a validated/verified domain under our merchant account which also means using localhost seems to be out of the question for local development. I was hoping that using the sandbox account would have been enough to maybe loosen up the domain requirement, but not so. Anything that can be set either on the account or in code to allow for the use of localhost with Sandbox accounts or is there some tool that I need to use for this or is this really only test-able under our sandbox domain?