I worked on the team that built the e-commerce functions for www.disneyworld.com back in 2012 when the site was completely rebuilt.
Payment and Checkout
For a company like Disney, the website is not just a website. It’s considered a part of the guests vacation experience. It has to be great. No, it has to be magical!
It was reconstructed using multiple layers but the top layer was PHP running Zend Framework. The middle tiers were Java applications deployed to Tomcat which did all the really dirty work of communicating with the numerous backend systems involved in purchasing tickets, reserving hotel rooms, flights, rental cars and more.
My team built the entire flow from the moment someone decided to check out until they had gotten their email confirmation.
Shortly after launching the site it was quite startling to see that the code we had written was processing millions of dollars in payments on a daily basis. Sites like this have so many visitors from all over the world that rare events most e-commerce sites can safely ignore would happen hundreds of times a day for us.