I designed, developed, and sold the front and back ends of the first version of the Enterrupt enrollment system. Enterrupt 1.0 is designed to operate with one foot in the proverbial cloud and the other embedded in a licensing institution's PeopleSoft database. The front-end lives on a cluster of AWS and Linode servers, while the back-end consists of a group of PeopleCode programs and a Java serialization library that resides on PeopleTools app servers.
Development of this system led me to most every corner of PeopleSoft: the web server, the app server, PeopleCode, and even COBOL. Enterrupt was licensed to the University of Virginia in 2013.