Using the API integration you need to care about four process participants:
our secuconnect API
our Smart Checkout
This is the process if the final confirmation can be handled by Smart Checkout (with auto_capture):
The customer details can be passed to the Smart Transaction in the beginning.
The payment authorisation can be more complex than you can see here. It can contain:
the selection of a payment method
to enter credit card details
to enter bank details and give a SEPA direct debit mandate
to make a 3-D Secure check for credit card payments, if required
to visit the PayPal payment page
Everything in this process is managed by our Smart Checkout, and you don't need to care for the details. The customer will only be prompted for the required decisions and details.
This is the process if the final confirmation must be handled back at the merchant's website (with explicit capture):
The only difference is in the final confirmation on your website. It requires another API call to start the Smart Transaction and capture the payment.