Third-party vendors are any service or advertiser that is not directly sourced from the hotel. There are hundreds of these services. They use Global Distribution Systems (GDS) where hotels voluntarily place inventory and rates to resale. The GDS are designed to give third-party vendors full capabilities to book rooms. They include companies like Costco Travel, American Express Travel; advertisers like Hotwire.com, Getaroom.com, and many others, and also thousands of small businesses, including local, independent travel agents.
Major third-party vendors include Hotwire.com, Getaroom.com, eDreams.com, HotelTravel.com, Travelocity.com, Bookit.com, Despegar.com, Jetsetter.com, Hotel.info, HotelReservations.com, OneTime.com, HotelsOne.com, amextravel.com, AMONA.com, cheaphotels.com, hotelscheap.com and many more.,