Arek Holko

About Me

Hi! I'm Arek Holko, an iOS engineer in Warsaw, Poland. You can subscribe to my newsletter to stay updated.

You can reach me via:


Fastest email cleanup

I joined the project while it was in the prototype phase, to plan and execute the work needed to bring it to the App Store. This is a model-heavy app that processes lot of emails doing everything locally.

Interactive guitar teacher (watch the video ๐Ÿ“บ)

I was mostly responsible for Chord Trainer (in the video above), everything from a flexible model up to a custom animation engine based on POP and Core Animation. Created by the team of eight engineers split into two countries. Featured on the App Store in Best New Apps.

Speed reading trainer (watch the video ๐Ÿ“บ) โ€“ Indie

I built it as an indie developer, along with a UI/UX designer. I created the whole codebase, made many mistakes and learned a lot in the process. Liked by the users (4.5-star rating) and featured on the front page of the App Store.

Platform for promoting art through apps

We built a flexible system for creating apps about art. As a lead developer, I created some technically-challenging parts of UI and helped bring the project to completion despite heavy time constraints.

OUTlife (defunct)

Social network for LGBTQ

I was focused on two parts of the app: model (based on Core Data) and the main feed infrastructure (based on ComponentKit and immutable models).


I find that writing helps me come up with better solutions to problems I think about. My articles are often featured by iOS publications, such as iOS Dev Weekly, NatashaTheRobot and iOS Goodies.

Here are some articles that you should start from:

See all articles.


Aside from writing, I recently got interested in public speaking as a way to share my knowledge (and learn from others too!):

Open Source

Over the years, I built many small, focused open source projects used in total by thousands of developers. Here are my current favorites:

See more on my GitHub profile.


I've been programming since high school. To keep my horizons broad, I got degrees in Mathematics and Finance.

I was fortunate enough to publish, in a top computer science journal, a research article: โ€œEpidemiological modeling with a population density map-based cellular automata simulation systemโ€.