This talk was recorded at NDC London in London, England. #ndclondon #ndcconferences #developer #softwaredeveloper Attend the next NDC conference near you: https://ndcconferences.com/ https://ndclondon.com/ Subscribe to our YouTube channel and learn every day: / https://www.youtube.com/channel/UCTdw38Cw6jcm0atBPA39a0Q Follow our Social Media! https://www.facebook.com/ndcconferences https://twitter.com/NDC_Conferences https://www.instagram.com/ndc_conferences/ #functionalprogramming #architecture #code Modern architectures (such as Onion, Clean and Hexagonal) recommend that interfacing with the outside world be done at the boundaries of your app, not in the middle. Similarly, in functional programming, the core code should be deterministic, and all I/O should be at the edges. But how can you actually do this in practice? How can you separate I/O from business logic in an elegant way? In this talk, we'll look at some concrete examples of how to refactor code in this way. We'll also talk about how doing this improves code comprehension, testing, and refactoring.