Amazon did not replace their monolithic Obidos architecture in a “big bang” replacement program. Instead, they moved to a service-oriented architecture incrementally, while continuing to deliver new functionality, using a pattern known as the “strangler application.” As described by Martin Fowler, the pattern involves gradual replacement of a system by implementing new features in a new application that is loosely coupled to the existing system, porting existing functionality from the original application only where necessary.9
