About me

Picture of me at Tahoe

I'm Agnes Vasarhelyi, a software developer from Hungary living in San Francisco. 🌁

I started this blog to let people follow my path as I evolve as an iOS developer. I'm an advocate of sharing knowledge and building our communities. This is the place where I collect everything I contribute to this cause.


You are already on it.

I have a few articles outside of this blog, namely on the Topology Engineering blog (the startup I worked with recently). Visit that to read my story of hunting down a mysterious Swift bug, learn how to love Auto Layout, or follow my struggles trying to figure out background sessions on iOS.

Organizing community events

Here are some conferences and meetups I organized, co-organized, or just working on right now!

Craft Conference '18

I was co-organizing this event by putting together a great mobile lineup for this conference in Budapest, Hungary.

Craft Conference '17

I was co-organizing this event by putting together a great mobile lineup for this conference in Budapest, Hungary.

Functional Swift Conference '16

It was an amazing two day conference in my hometown, Budapest. I loved every minute working on it. ☺️ I wrote a blog post about the whole story.

NSBudapest meetup

This is the iOS meetup of Budapest, a great effort backed by several local startups throughout the first year (2016) of this awesome monthly event. The organization is 100% transparent and open source as well as the goal: connect Apple technology enthusiasts and let them evolve together. We have presentation style events, workshops and small roundtable sessions as well.

Native Development meetup (extinct)

The first meetup I was participating in organizing where the goal was to create a community for people interested in any kind of native development like any mobile or desktop technology, tool, or method.

Public speaking

I got into public speaking recently, here are my talks so far. Feedback is very welcome!


Exciting news coming soon!


The complicated life of a backgrounded iOS app

360|iDev, Denver, CO - August 26-29, 2018

Background transfer is an invaluable feature if your app is relying on any critical network operation that could potentially drive your user’s attention away when running long, or being interrupted.

There are non-trivial challanges to solve before being able to support it in your apps though. Including limitations around authentication methods, response/error handling, and keeping the mysterious resume rate limiter happy.

After solving this puzzle with some pieces under-documented, almost impossible to debug and nerve-wracking to test, I’m here to share all our findings to help you understand and work comfortably with background sessions.

Simple Layout of a Complex Interface

Swift Fest, Boston, MA - June 18-19 2018

Understanding Auto Layout is your best chance to write UI code you can be proud of. Its power often underestimated, its features easily misused, I find it overall less appreciated than it could be, if more widely understood.

This talk is aiming to show how relying heavily on Auto Layout makes you move faster and be more confident writing UI code. Working with the safe area, showing off custom UILayoutGuides and making use of the controversal UIStackViews, we will walk through the simple code of a more complex interface together.

Seven easy ways to Auto Layout confidence

NSMeetup, San Francisco, CA - May 9 2018

Working confidently with Auto Layout is the way to write simple and robust UI code. Auto Layout gets dismissed for being too difficult to use and debug, but it has power and elegance just below the surface. This is why we need more discussions around it!

In this talk, we’ll walk through the ways Auto Layout makes you move faster and be proud of your UI code. Discussing the safe area, custom UILayoutGuides and the controversial UIStackViews, we will see how to create a more complex interface with simple layout code.


Everyday Reactive

try! Swift Tokyo, March 1-2 2017

In this talk walks through some practical uses of reactive programming in app development, using examples from my daily experiences in the past. Explores tips and tricks for determining when reactive programming can be a potent tool, as well as scenarios to avoid that might threaten code quality and performance. The talk focuses on concepts in reactive programming, the code shows off different Swift reactive implementations.


Styling iOS apps Swiftly

NSSpain, Logroño, 2016

Almost the same talk as Swiftly Styled below.

Swiftly Styled

Forward Swift conference, SF, 2016

This talk is about how working with stylesheets helps devs & designers work better together on UI code.

Inspired by FRP

Craft conference, Budapest, 2016

The goal of this talk was to share how the original ideas of Functional Reactive Programming invented decades ago, influenced reactive programming libraries like ReactiveCocoa and why is it important to understand the relation. Some bad examples of over-using reactive and pro-contra arguments.

ReactiveCocoa reloaded

MCE conference, Warsaw, 2016

An overview about the differences between using Objective-C API of ReactiveCocoa v2 and Swift API of v3 (alias v4).


Functional Thinking

Functional Swift Conference, NY, 2015

This talk meant to be about how the ideas from functional programming can be leveraged even on a higher abstraction level when designing an application from little boxes of functionalities.

Evolution of a beer brewing app⚡️

Swift Language User Group San Francisco, 2015

My story about how I managed to try out several interesting technologies, like React Native, ReactiveCocoa, Carthage, and Bitrise in the same pet project, an iOS front-end for my friends' automated beer brewing system, Brewfactory.


If you have any thoughts on the blog, my talks, or anything related, please drop me a line on Twitter, any feedback is much appreciated. 💜

Last edited: November 2018.