Home Online payments ... Drop-in Advanced use cases Advanced use cases Learn about advanced use cases with iOS Drop-in. The iOS Drop-in integration handles the entire checkout flow by default. However, there may be some cases requiring you to make /payments or /payments/details requests from your server.: Update the payment amount, for example if the shopper updated their cart during checkout. Confirm an additional action on your server, in case the shopper had to do additional actions such as authenticating a payment with 3D Secure.