Can I cancel a flight ticket and get my customer a refund through the API, or do I have to contact the airline myself?

Yes, in most cases you can cancel a flight booking and start the refund through the flight booking API, without calling the airline yourself. You send a cancel request with the booking reference, and the response tells you whether the cancellation went through and what penalty the airline is holding back, so your team can handle it from your own portal.

How far you can go depends on the fare and the supplier. Some fares are non refundable, so you only get taxes back, and a few give back nothing. Low cost carriers often do not allow cancellation through the API at all, and those have to be done on the airline side. Timing matters too, because once the flight has departed or the ticket has passed its time limit, the API will usually refuse the request and it becomes a manual claim with the airline.

It also helps to keep cancelling and refunding apart in your head. Cancelling stops the travel. The refund is money moving, and that takes longer, because the airline has to process it and then it has to reach the card or account that paid. The API can confirm the refund was requested and what was approved, but it cannot make the money arrive sooner.

Before you promise this to a customer, read the cancellation rules that come back with each fare at search and booking time, and ask your supplier which airlines support cancellation through the API and which need to be done by hand. Knowing that in advance saves an awkward call with someone expecting an instant refund.