Though working as an offline mechant, we are considersing online payment now to reduce payment time for customer. We need your help to find out a end to end solution for our scanarios.
Here's our service process plan:
1 We have a website to manage our order, and would like to integrate paypal or Venmo here to request for a payment from customers;
2 We provide a android APP for customers to check their orders, and would like to integrate paypal or Venmo there to accept a payment request from mechent;
3 Customer configure their paypal/Venmo accounts in our APP before shopping, and agree for being charged automatically by us.
4 After customers are done their shopping, they don't need to wait for checkout. Mechant can check customers cart online and generate bill and charge to customer through paypal/Venmo online with the paypal/Venmo accounts they've configured in our APP; No device/hare equiment is needed.
5 From customers side, there's no action needed for the charge. Custmers can check the order and bill list at anytime in our APP.
Could you please help to give a hint how we can implement that? And which API/SDK should we use?