GDS, on travel and tourism industry, means Global Distribution Systems.
These systems connect globally, through Internet, hotels, airlines, car rentals, and tourism services suppliers in general. GDS make tourism services available, globally, to a large chain of travel agents and tour operators.
Some services suppliers, for particular reasons, are not connected. It's unnecessary to say that they lost business opportunities when their services are not being exposed to the global market.
An small hotel in Switzerland. It's undeniable, independent where your business is, it's strategic to expose your services to a global market, making it instantly available to an army of travel agents and tour operators. Photo by Nigel Tadyanehondo.
Main GDS systems
Today, Amadeus, Sabre, and Travelport have the largest market share. There are, and there were, others like Abacus, TravelSky, Apollo, Worldspan, Galileo, etc. Some of them were acquired and incorporated by others. Travelport has acquired, per example, Worldspan and Galileo.
Like in other fields, GDS companies can merge and be acquired all the time.
GDS that EasyPNR officially supports
EasyPNR is free, reliable and officially supports Amadeus, Sabre and Travelport (Galileo and Worldspan)