I did large scale e-commerce at Avnet from 2000 to 2003 for an annual revenue of $12 billion.  My team wrote Q2O (Quote 2 Order), a sales tool which was a significant success and transacted $1.5 billion in its first year.  Later I worked with IBM's Websphere Commerce Suite, a highly configurable, highly scalable e-commerce system similar to AWS or Azure (1000 configurable database tables and 100K java classes).   My work including LDAP, single-sign on, payment interfaces, database schema extensions, UDDI (web service registry) and MQ Series integrations to other systems.