How do online booking system works?

          

How do online booking system works?

The online system you see may link to a number of other systems.   For instance, most airline reservations are made via the API provided by one of the GDS (Galileo, Sabre, Amadeus etc).   They, in turn, connect to the airlines through long establised communications system the oldest of which is computerised telex messages.   The website may cache some response from the GDS and use them to offer fares, only going to the GDS when the passenger says "yes".   The GDS may also have cached some answers.   The result can be that the website offers a fare and the airline says "no".   Add to that the fact that some of the actual fares are stored in a system operated by the agency which means the agency system has to go there, determine if they have a "special fare" then go to the GDS and they go on to the airline to determine availability and it all gets messy.

Some hotels and cars are also served by the GDS.   However, with hotels (and a lesser exten cars) there are some wholesalers in the mix as well.   They negotiate rates with the hotels, add their own markup and sell direct to the public but they also offer rates via third parties at rates which may not be the same as the rates on their website.   The ultimate seller probably adds his own markup so you need to factor that calculation in.   All of this is done via APIs (or an earlier version an XML message set).   Of course, one website may be connecting to a GDS for some hotels, a wholesaler for others direct to an hotel (group) for others.

Once you've got someone hooked in to make a booking you need some kind of storage to record what they've done and connection to at least one payment gateway to collect money from credit/debit cards.   In some countries there may also be ways of paying - at least one Asian market allows people to make a booking and then go to an ATM to pay.   In all those cases you need to be able to manage what happens if the payment fails.

Then you have to consider, changes made by both the passenger and the vendor (e.g. schedule changes), refunds, complaints etc.   It's also the case that different websites have different business mixes.   Theatres, concerts, railways, long distance buses, ferries, cruises, all inclusive package holidays and festivals to name but a few all of which have different detailed methodologies.