PHP + PayPal: make payment by PayPal without screen login

I have a new question. This is my context:

I want to make my own API REST, where I can call this method with information about my product as parameters. My backend method do the typical purchased process but it doesn't show the PayPal screen which show information about my product, just do the process directly and I receive an answer. Is it possible?

I'm using the PayPal SDK for PHP, and looking for at Google I just have gotten that the PayPal page shows, but I'm new in this. Your answer will be so good!

via Chebli Mohamed