Paypal and Payoneer users' validation API

I wrote a web-site and I want to connect the users at some point to there Paypal and Payoneer accounts. I saw some very开发者_C百科 old posts (even in Stack overflow) that said it wasn't possible.

Does someone know if something has changes? Is it possible to do so?

I haven't used the API myself, but here is the link for the Paypal Account Authentication API. I couldn't find much about Payoneer, except that they are thinking about making a SDK.