I am currently the DBA on a large scale multi-tenant payment portal system. I am the original architect of the database design which was structure for flexibility in it's management of document, user, and payment information. The payment portal tenants include major healthcare, financial services, and utility companies. The application is only a few years old, and we are approaching 1 billion dollars in payments processed.
I also develop software in C#.Net with expertise in RESTful API, screen scraping, n-tier applications, and more.