Can the hotel booking API give me a voucher I can send to my customer to show at check in?

Yes. Once a hotel booking is confirmed, the hotel booking API gives you back everything a voucher needs: the hotel name and address, the guest names, the room type, the board basis, the check in and check out dates, and the supplier's confirmation reference. Most portals take those fields and produce a PDF voucher carrying your own agency name and logo, which you then email or message to your traveller.

How much that voucher is worth at the front desk depends on the supplier. Some suppliers issue their own voucher document and expect the guest to present that one. Others are happy for you to generate your own, as long as the supplier reference is printed clearly on it. A few pass the reservation straight into the hotel's own system, and the guest is simply found by name. The safest voucher is one that shows the supplier reference at the top, so the hotel can trace the booking whichever way it reached them.

Be careful about sending a voucher too early. If a hotel is on request rather than instant, the API will give you a reference before the hotel has actually agreed, and a voucher sent at that moment can leave your customer standing at a desk with no record of them. Wait until the booking status is confirmed. It is also worth checking whether your supplier allows their name to be hidden, as some contracts require the guest to see who the room was booked through.

Before you send your first one, make a test booking, look at exactly which fields come back with the confirmation, and ask your supplier whether their own voucher must be used or yours is accepted.