Who am I?

My name is Krzysztof. I'm an iOS developer and a cultural anthropologist living in Warsaw, Poland.
Do not hesitate to get in touch. I'm @_siejkowski on twitter and siejkowski on github. You can also find me on linkedin.

Personal projects

Video Game Music app (early in development)

iOS app for exploring, enjoying and celebrating the world of video game music. It's a catalog of game soundtracks, arrangements and tributes. You can easily find the tunes from your favourite games and discover new ones. If you have a Spotify or Apple Music account, you can start the playing music directly from the app.

Being developed with SwiftUI, Combine and The Composable Architecture.


Collection of the code poems I wrote in Swift programming language.


How to Build Swift Compiler-Based Tool? The Step-by-Step Guide

Open Source Code Obfuscation Tool for Protecting iOS Apps

RxSwift - Mistakes to Avoid. Part 1

Trimming Swift generics

Road to Mobilization: Typeclasses in Swift, Haskell and Scala


Container types and how to use them — 2019/04/17 — CocoaHeads Lodz meetup #29


Matryoshka in Swift: Handle nested containers with grace — 2018/11/19 — Mobile Warsaw meetup #66

Video / Slides

How to use container types in Swift and not 🤯 — 2018/06/26 — Swift.map{5} meetup

Video / Slides / Github

Take the compiler and run with it: a quick story of Swift obfuscator — 2018/06/06 — MCE 2018 conference


How to use Swift compiler as a library? — 2018/05/22 — Mobile Warsaw meetup #61

Video / Slides

RxSwift: Deep Cuts — 2017/10/21 — Mobilization 2017 conference

Transcript / Slides

A Neatly Typed Message: Improving Code Readability — 2017/03/03 — try! Swift Tokyo 2017 conference

Video / Slides

RxSwift: an elegant weapon for statically typed age — 2016/04/11 — Mobile Warsaw meetup #36

Video / Slides

swift-for-backend-SNAPSHOT-2016-03.tar.gz — 2016/03/31 — Swift Warsaw meetup #6

Slides / Github

Dobry zwyczaj: nie odziedziczaj — 2015/10/17 — Mobilization 2015 conference

Video / Slides

swift-dsl-toolbelt — 2014/07/31 — Swift Warsaw meetup #1