We work in scrum. Our sprint lasts 2 weeks, we ship to the store every iteration. Our application is used by hundreds of thousands of people worldwide. We use Swift as our main language, but some parts of our product are (still) in Objective-C.
We iterate over problems, we experiment and measure how our solutions impact the end user, and we learn how to improve at every cycle. You can try our solution at zefiro.me and download the Zefiro Cloud android and iOS app
