I'm desperate for a payment solution for a very specific problem that requires third-party widgets to solve, so I can't directly use the PayPal button code. These widgets appear to require the three-part NVP/SOAP API authentication, consisting of Username, Password, and Signature.
One of these widgets explicitly labels the PayPal integration as Express Checkout. In that widget there is a drop-down for selecting between payment processing options, and when PayPal Express Checkout is selected, the three fields for the Username, Password, and Signature appear.
The other widget does not explicitly name the PayPal feature as Express Checkout. It just contains fields for the API Username, Password, and Signature.
I don't understand exactly what Express Checkout is. Wherever the three-part API authentication is required, does that mean that Express Checkout is the specific PayPal product that is being used behind the scenes?
If so, is there a difference in the requirements for the state of the receiving PayPal business account depending on whether or not the NVP/SOAP credentials are being used with Express Checkout?
I ask because one of the two widgets keeps redirecting back to the homepage after a checkout attempt with the string "?payment_error=1" added to the end of the URL. I've described this behavior more thoroughly in a question that I accidently posted to the Community forum rather than to this forum:
/t5/About-Payments/Getting-payment-error-1-appended-to-redirected-URL-after/m-p/1163736
I've been communicating with the maker of that widget, and I agree with him that this problem probably indicates some kind of PayPal authentication problem, because it proceeds to the PayPal checkout, and PayPal redirects back to my website with the error code appended to the URL.
I'm using real credentials generated from a business PayPal account. (I now understand that using sandbox accounts isn't going to work with the widgets, because they don't implement the sandbox environment.) I don't have any reason to believe that the API credentials are incorrect, because they were copied and pasted. On the contrary, I have reason to believe that they are probably correct, because one of the widgets simply wouldn't proceed to the PayPal checkout when I was trying to use sandbox credentials or when I first tried typing in the strings for the real credentials. However, I'm not sure if the account associated with these credentials is configured correctly or at the right service level to use whatever product these widgets are trying to connect to. (I'm not even sure that they're trying to use the same product behind the scenes, even though they both ask for the same API credentials. One of them simply uses PayPal as a gateway to process credit cards, the other redirects to the standard PayPal checkout.)
I have not yet been able to verify a successful transaction with either of these widgets. I've been trying $0.02 transactions, and so far none have showed up in either the seller's PayPal account or the buyer's PayPal account. I was acting as the buyer with my own PayPal account, so the same account is absolutely not being used as both the buyer and the seller.
Is there some test I can run to determine if the credentials are authenticating all right? Is there some way I can test whether the account is valid for Express Checkout? Is there some way I can get a specific error code so I can better determine what is wrong with the account?
Any help is greatly appreciated!
