Many payment methods are asynchronous. Thus a shopper could be redirected back to you with the result of the payment still being unknown. This is the PENDING status. You should maintain an open record in your system for these payments until you receive the final status of AUTHORISATION.
The final status will be communicated via the AUTHORISATION Notification with
success=true when a payment is successfully authorised, or
success=false when a payment is refused. Refer to the Notifications page for more information.
Occasionally, the final status of a payment may not be known for an extended period of time or a final status may never come through. It is recommended that you expire these payments after a certain time interval, since you don’t want to maintain the open record of a potential payment forever. Each payment method has it’s own expiry timeline for how long a PENDING status should be kept open.
Depending on the payment method there is a difference on whether a pending state can occur and for how long a payment can exist in this pending state. While in most cases after the shopper has been redirected the payment only stays Pending for a few minutes, in the case of cash and voucher based payment methods commonly the shopper has a few hours or a few days to pay by cash in a local store: in specific cases the expiry date can be set by the merchant. For online banking payment methods a pending state could occur for some specific payment methods or banks if settlement cannot be confirmed: in this case it could be a few days before the payment is confirmed, especially when the payment is done just before or in the weekend.
Make sure you implement the PENDING status. Though some payment methods do not have a PENDING status, most do, and implementing PENDING will ensure that adding any future payment methods will not require additional development work on your end.