Is there anything on my portal that stops people booking flights with stolen credit cards?

Yes, there are several things you can put in place, although no portal can stop card fraud completely. The first line of defence is your payment gateway rather than the booking software itself. Most gateways offer card authentication, where the customer has to approve the payment through their own bank app or a code sent to their phone. When that check is in place, many banks treat the payment as verified and the liability for a disputed charge often sits with them rather than with you, but the exact rules depend on your gateway, your acquiring bank and the country the card was issued in, so please confirm that with them directly.

On the portal side, the main protection is not issuing the ticket the instant the payment goes through. You can set things up so that bookings come to you for a quick look before they are confirmed with the airline, which gives you a chance to spot the ones that feel wrong. The usual warning signs are a booking made for travel the same day or the next day, a passenger name that does not match the cardholder, several attempts with different cards, or a route that has nothing to do with where the customer says they are. Whether you can apply this review step to all bookings or only some of them depends on your plan and on how your gateway is set up.

There are also simple habits that help. For a high value or very last minute booking from someone you do not know, it is reasonable to ask for proof of identity before you issue, and to keep a record of what you checked. If anything looks off, cancel and refund rather than ticket and hope.

The best next step is to ask your payment provider exactly what fraud screening and card authentication they include, then tell us how you want risky bookings held for review so we can match the portal settings to that.