Functional Programming is sold as a silver bullet. Yet most organizations lack real-world experience with the paradigm. It’s hard to adopt functional programming too since most public examples show small and isolated code snippets and it’s not clear how those pieces would fit together to form a system, a functional architecture. A real-world system also has to deal with non-functional side effects and the rapid feature growth of an evolving product. So how well does functional programming work in practice? What happens when you bet your company on a functional programming language? Will the hype transfers into productivity gains and cheaper maintenance?