A picture from Mozilla Festival 2014. All participants are in a circle.


I'm Errietta Kostala and I'm a full stack developer...

with a passion.

Learn more

Ever since I was a teenager, I knew I wanted to be involved in programming. I spent countless hours working on my own projects, learning more and more and becoming more and more fascinated. To me, programming is an art form, a poem, a song, a dance.

But in time, it became something even more. As I started getting involved in freenode, Mozilla, and other open source projects, it became a way to be part of a community - I could network, make friends, and meet people that would be with me for the rest of my life.

It then became clear to me - I didn't just want to follow my passion of programming. I wanted to teach others what I knew. And I wanted to keep supporting Open Source projects and helping others.

For this reason, I studued Web Technologies at the University of Huddersfield - so that I can learn even more about what I'm passionate for, and I did an internship for Shadowcat Systems - a small company in Lancaster that holds open source and community projects very dearly.

I currently work as a back-end developer for FairFX, a foreign exchange company, and I still spend a lot of my time on community projects.

Do you want to learn more about me? Check out my projects or my blog.

Latest blog posts

Debugging with the JavaScript debugger

The Javascript debugger is a great tool for seeing how an application or page behaves or solving a problem when it’s not behaving the right way – without consoie.log all over the place. In this article we will have a look at how it is used. Let’s have a look … Continue reading

Angular 2: Property binding, event binding, headaches

I have been looking at Angular 2 lately. After being disappointed with the tutorials online, I decided to write my own cookbook on property and event binding. Property binding Assuming we want to pass myProp from my-parent to my-child, we need the following. 1) In my-parent template: <my-child [myProp]="prop" /> … Continue reading

[vlog] How not to design a User Interface: lessons from Nintendo

[vlog] this year’s uni projects

It’s … been a while, hasn’t it? Okay, okay, it’s been three months. I’m currently buried underneath 6ft of Uni work, given this is my final year and my dissertation is due soon. I’ll try to blog more often once I get into full-time paid employment. However, until then, here’s … Continue reading

A first look at Cordova: pros and cons

I absolutely love the fact that tools like ionic and Cordova exist. It  means that Web Developers like myself can build hybrid applications (apps that work in both web and mobile) without needing to write native code. However, this doesn’t come without disadvantages. Due to this, I wanted to write a … Continue reading


So far as I'm concerned, you write sane code, and you ask when you're stuck, and you listen to design ideas and then ask questions and then implement them.

Matt Trout, Shadowcat Systems Technical Director.

We get a lot of contributors but it is not every day someone so seamlessly integrates with the entire team. I went away on vacation and when I came back Errietta was an integral part of our work environment – a powerful presence on IRC, at our video demo call and on GitHub. I hope she continues to lend us her talents for a long time to come.

Cassie McDaniel, Webmaker UX Lead (Source)

Errietta has all the qualities of a great web developer in the making — she learns quickly, values feedback from both engineers and designers, and cares deeply about sharing her knowledge with others. I'm always impressed by how quickly she's willing to jump into a new code base and effectively solve problems.

Kate Hudson, Webmaker Developer