Karolina Samorek | skarol.dev

Hi, I'm Karolina,
Lead iOS Engineer at Lake.

I write about building iOS apps, the iPhone Duo and working with AI coding agents. I also made duoctl, an open source tool for testing apps on the iPhone Duo simulator.

More about me on the Experience page. Featured in SwiftLee Weekly and iOS Dev Weekly.

Getting your app ready for iPhone Duo: what actually broke

19 Oct 2026

iPhone Duo ships on 23 October, and Duo screenshots become mandatory for new App Store submissions in April 2027. Here is what broke when we ran a real app on it, and the checks I'd do first.
Where did my disk go? Xcode, worktrees and AI agents

12 Oct 2026

Running AI agents on an iOS project in parallel worktrees quietly eats disk space, and when the disk fills up, Xcode reports everything except a full disk. Here's where the space goes, how to measure it honestly and how to keep it under control.
Scripting the iPhone Duo simulator: how Device Hub folds, rotates and touches it

07 Oct 2026

Xcode 27.1 ships an iPhone Duo simulator. Device Hub can fold it, rotate it and tap both of its screens, but nothing scriptable could. So I watched what Device Hub does and built duoctl.
Why we fail to keep good-quality software

07 Mar 2018

When you become a programmer, you hear a lot that you need to deliver good-quality code. The code should be readable and easy to understand for other developers. It should also be maintainable. Oh, and you should write unit tests...