Will I know if there are local taxes or resort fees my customer has to pay at the hotel, or will they only find out at check in?

Yes, in most cases you will know before the booking is confirmed. Hotel suppliers usually send the charges that are payable directly at the property as part of the price breakdown in the API response, and your portal can show that separately from the amount your customer pays you online. So the room page and the checkout page can both make clear what is prepaid and what the hotel will collect at arrival, such as city or tourist tax, resort or facility fees and certain parking or wifi charges.

How clearly this appears does depend on the supplier and on the individual hotel. Some suppliers send a tidy figure with a note about when it is collected and in which currency. Others send only a short block of text from the hotel, which we can display but cannot neatly separate into its own line. A small number of properties send nothing at all, and in that case your portal cannot invent the information. These charges are also set by the hotel or by the local authority, not by us or by the supplier, so they can change between the day of booking and the day of arrival.

What you can control is how plainly it is presented. The payable at hotel amount can be shown on its own at checkout, repeated on the voucher so your customer has it with them at the desk, and kept out of your own markup so your margin sits only on the money you actually collect.

Before you go live, run test searches on a handful of hotels in the destinations you sell most, compare how each of your suppliers returns this information, and add a short line in your own wording at checkout so nobody is surprised at the front desk.