Can I sell a trip where my customer flies to several different cities on one booking?

Yes, in most cases you can. A flight booking API usually supports what is called a multi city search, where instead of a simple return journey you build the trip leg by leg, giving each leg its own departure city, arrival city and date. The search then comes back with combinations that cover the whole journey, and you can price and book it as one itinerary with one booking reference.

Booking the whole trip as one itinerary is normally the better option for your customer, because the airline treats the journey as connected. If a delay on an early leg makes them miss a later one, the airline has a duty to help. Sometimes the cheapest result will instead be separate tickets stitched together, and in that case each ticket has its own rules, its own baggage allowance and its own refund terms, and a missed connection is your customer's own risk. If you present that kind of option, please explain the difference to them before they pay.

There are honest limits here. How many legs you can add, and whether the journey can start in one city and finish in another without flying back, depends on the airline fare rules and on which suppliers are connected to your account. Budget airlines often cannot be joined into a single itinerary at all, so a trip that mixes them with a full service carrier may have to be issued as separate bookings.

The quickest way to know what you can offer is to run a multi city search on a route you sell often and look at what actually comes back, and ask us which of your connected suppliers handle complex journeys best.