If my customer cancels their flight, can the portal tell me how much money they will get back?

Yes, in most cases the portal can show you an expected refund amount before you confirm the cancellation, but that figure comes from the airline or the supplier rather than from us, so how precise it is depends on the fare your customer bought and on what the airline sends back.

Every ticket carries its own fare rules, and those rules decide whether the ticket is refundable at all, what penalty the airline keeps, and whether any part of the taxes comes back. Some airlines and suppliers return a proper refund quote through the API, so you can see the deduction and the net amount on screen and show it to your customer straight away. Others only return the fare rules as text, and the real amount is confirmed once the cancellation is actually processed. On top of the airline penalty there may be a supplier service charge and whatever fee you choose to keep yourself, so the amount your customer receives is usually less than the headline refund.

Timing is set by the airline and by the payment route, not by the portal. Card refunds generally find their way back through the same card that paid, and that can take a while even after the airline has approved it. Low cost carriers often behave differently again, and in some cases unused taxes have to be claimed manually through your supplier rather than automatically.

Before you promise a customer anything, open the booking in the portal and read the fare rules recorded at the time of ticketing, then ask your supplier whether refund quotes are returned automatically for the airlines you sell most.