After working on iOS apps for many years (Objective-C and Swift), last year I learned to develop web apps using JS and React. That’s when I started using Redux, which implements the unidirectional data flow architecture pattern. Immediately liking it, I then started using the same pattern on iOS using Swift. This talk explains what unidirectional data flow architecture looks like, why I like it so much, and how you can use it in Swift. For those who never heard about this, I hope to inspire you and give you a very powerful tool for building large apps. For those who already use it, I hope to give you a more profound understanding and the ability to better explain it to others.