depending on the payment method chosen by the user, sometimes I must open it in a new window. Which could be the best way to manage this action? The look and feel of the new webpage is completely different from the checkout one and it could generate a dismiss action of the payment by the user.
In some payment methods, like Paypal, you do need to redirect the user to a third party environment, and it's certainly some undesired friction. To mitigate that, you have to make it clear to the user what is about to happen. State:
• that the user will be redirected to a specified third party website and that he will be brought back to your website once the task is complete.
• the step in the process he will land on once he is back.
• None of their information will be lost