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

I survived a year at Shadowcat!

As you may know, I did a placement year/”year in industry” as part of my University degree. This is basically done in one’s third year of studies, before their final year and it helps get experience in the ‘real’ world before graduating. I had the ability to do a placement … Continue reading

Mozilla conference at Whistler, BC

I had the pleasure to spend the week of the 22nd – 27th of June in Whistler, BC for Mozilla’s all-hands conference, called Mozilla Work Week. The invitation came out of the blue, and I am extremely grateful to have received it! I could say that it was some of … Continue reading

Form sins: part two

This is a continuation of my previous rant on mistakes web developers make that make forms unusable. Here are other things I’ve noticed, mostly about forms that need your address: Requiring a ‘middle name’. They’re not used in every country in the world. Having a broken country input. This, in … Continue reading

Web forms

Web forms. They are used everywhere. Yet I have seen so many things done in them, that have made it difficult for even myself (a tech-savvy user, a web developer) to fill in. This should not happen. Filling in web forms is required for many reasons, yet to many users … Continue reading

Calling all women in IT

Hello, So, being on the Internet a lot, I’ve seen several tweets from tech event organisers that have had difficulty finding women in IT to invite to their talks. While I understand there are (unfortunately) less women in STEM than men, I know that there are still many very talented … 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