Keleigh Zolnierek – Software Development Engineer in Test

Keleigh Zolnierek – Software Development Engineer in Test


Software Development Engineer in Test – User Sessions
Chicago, IL
Joined: 2016

Test Engineer Keleigh pays it forward by participating in programs and volunteer efforts focused on building, developing, and motivating women in Technology.

What’s your favorite Groupon memory?

The first time I helped with Scout Out Engineering, I was so impressed by how much the scouts knew. It seems like schools have started teaching basic computer science concepts in elementary which is awesome!

What were you looking for in a company while you were job hunting?

Prior to joining Groupon, I interned at Thompson Reuters over the summer. It was an excellent internship program and the people who worked there were incredible. When I was looking for a full-time position, I knew that I wanted to move out of Michigan (which is why I did not choose Thompson Reuters) and that I still wanted to do Software Development. After that, I also focused on companies that would allow me to grow my career and further my programming knowledge. I was not sure that I wanted to work in Test Engineering, but decided based on other factors, such as location, benefits, and the people, that it would be the best fit at the time. I am happy with where I ended up and think it turned out well.

What does your family think you do?

Mom: “Test and fix computer programs”

Dad: “I really don’t know…..” (After telling him to guess.) “Responsible for the quality control for previously designed programs.” 

Brother: “Find mistakes.”

I’m very impressed with all of the answers! They are way closer than just making cool Powerpoint slides, which is what they thought for a while in college.

What’s unique about Engineering at Groupon?

There is always someone willing to explain a concept or process when you have questions about it.

What was your first impression of Groupon?

My very first impression of Groupon was at the career fair. They were one of the few companies that had t-shirts in women’s sizes and fits which impressed me. When I interviewed, I really liked how casual, yet knowledgeable the interviewers seemed. Also, it probably did not hurt that my interview in the Palo Alto office ended with fro-yo. 🙂

Can you tell us about your work promoting women in Tech?

I’ve recently started co-leading Groupon’s Lean In Circle, which is currently based in Chicago; however, we do have an engineer who joins from Palo Alto. We meet regularly to learn and grow together, specifically in the engineering space. There are three areas we focus on: professional, leadership, and technical development. We hope to grow our circle to include more women from different Groupon offices.

What’s surprised you the most about working at Groupon?

The random company things that Groupon does are awesome. Some of my favorite things were Halloween caramel apples and cider last year, laptop stickers, Women@Groupon handing out ice cream, the building’s ice cream social and rooftop doughnuts, and Geekfest weekly tech presentations (which are open to the public). These seem like small things, but I really appreciate them.

Tell us about the SDET team.

As an SDET there are a few different team setups at Groupon. For my team, I have two sections: my testing colleagues and my feature team. My testing team is made up of SDETs who are also doing front-end testing for Groupon. With that team there are different features—such as internal tools or frameworks—that we develop.

My feature team is the group of people who are responsible for testing the user sessions material. The people included in this are a team manager who makes sure our team stays on track for team goals, a product manager who decides what new features we will try out, a developer who turns the feature ideas to code, two Software Test Engineers who manually test features, and me who automates the testing process!

What’s your favorite language?


What’s your favorite part of your team’s software development process?

I really like when we find a bug. If there aren’t any found, it makes me a little nervous and I feel like we may be missing something.

How does your work connect to Groupon’s mission of building the daily habit in local commerce?

I make sure that the sign-in page is not broken so users are able to make purchases.

What are your favorite local businesses?

Doughnut Vault and Mindy’s Hot Chocolate.

Vim or emacs?

Vim, because it’s what I used in school.

Tabs or spaces?




Groupon World Headquarters

How did these Engineering interns tackle Groupon’s giant code base?

How did these Engineering interns tackle Groupon’s giant code base?

Two interns-turned-employees share their experiences working at Groupon in both Engineering and Data Science.

What have you both been working on?

Sunil: I work with the Ranking and Personalization team in Palo Alto and we’re responsible for mining deals that are relevant to the customer. When you open the Groupon app on your phone or visit the desktop site, what you see, how you see it, and the order in which you see content is determined by the recommendation algorithms developed by this team. Every deal that shows up has to pass through a series of features, each of which does some processing, prediction, estimation, and finally assigns a score to the deal. The scores assigned by these multiple features are then combined to form a final score which determines the ordering of that deal on your homepage. Of course, there needs to be some way to make sure that the feature is actually improving user experience and is working for the benefit of the organization. And who would be a better audience to judge improvement in user experience than our users themselves? This is where the idea of live experiments fits in. All the features have to pass through an experimentation phase before they can be put into production.

Just like the deals, every user request also passes through a series of layers called “orthogonal layers.” This is the place where experiments are set up. When a user request passes through a layer, it decides what treatment the user will receive for that particular layer. It can be either the control treatment (baseline treatment which is running in production) or any of the experimentation treatment set up in the layer. The success or failure of an experiment is determined by comparing its performance with that of the control treatment. The percentage of traffic that will receive any particular treatment is adjustable. So usually an experiment starts with, say, 10% and then if results seem promising, it is ramped up to 50% and then finally to 100%. The most amazing part of the entire process, though? You get to know the approximate impact in the actual dollar amount of your individual work on the organization’s revenue. How cool is that?!

Nicholas: Pretty cool! I am also on the Ranking and Personalization team and I work on evaluating the performance of experiments and other changes to the ranking code. I own the performance testing tool which builds, deploys, simulates website traffic, and creates reports for the results. There are so many different orthogonal layers and experiments that all need to be compared, but there are simply too many to include in just one report. To make matters more complicated, each experiment has hundreds of metrics that all need to be considered to decide if an experiment is safe to add or ramp up. During my internship and my first two months as a full-time developer, I worked on building a self-service dashboard for scheduling and queueing performance test runs. Now that the dashboard is functional, I’m working on collecting runtime data with instrumentation and building infrastructure to support searching and visualizing all of the data we have available.

What are your favorite parts about working at Groupon?

Sunil: The flexible work environment and unlimited PTO policy are the top reasons I love working here. Of course both free lunch and paid lunch hours help, too. But it’s not just about the flexibility in free time, it’s also about the flexibility in the work that you do as a part of the team. There is freedom in the kind of work that you want to do, the projects that you want to work on, and the ideas that you think should be explored. 

Nicholas: My favorite part of Groupon is the scope and influence I have on the projects I work on. Since every code change needs a performance run, I’ve had the chance to work with most of my team members to schedule custom runs and help with debugging. I love being able to support all of my team members, and my work helps all of them to be more efficient. I appreciate being able to decide what tasks are the most important to meet the needs of my team. Also, the proximity to the Caltrain station is so convenient; the station Sunil and I both get on is next to the Stevens Creek trail, so I get to bike along the trail to work every day. 

What do you think you’ll both gain as new grads?

Sunil: There is a lot to learn about how the infrastructure is set up to manage a huge service such as ours: a lot of different technologies and languages that are used within the organization (two new languages already in my first two months) and the coding guidelines which are checked to ensure clean, sustainable, and functional code…especially for somebody who just graduated and is used to all sorts of nonsensical variable naming and structuring. There is also a lot to learn about how to build upon any ideas that you might have in mind and the ability to think out the entire process of transforming an idea to a feature in code.

Nicholas: Groupon is a great place to work because it has the resources of a large company, but there are so many important projects that a new grad like me can work on. I have encountered all sorts of challenges that need to be dealt with when scaling a small project to a reliable service. Many features that seemed trivial to implement at first required me to learn about different designs and frameworks that I never needed when my project was small.

What has your biggest challenge been so far?

Sunil: To be honest, I felt a bit intimidated when I first saw the enormity of the code base. This was during the middle of my internship when I had completed data analysis and offline model training and had to start getting my hands dirty to move the model online. I was running short on time before my internship would end because it had taken more time than planned to build a model due to some infrastructure as well as data sparsity hurdles. It took me quite some time—days, really—just to determine a starting point. After a couple of days of staring at this overwhelming code—and of course, with some help—I figured out where to start. I do think that staring at and absorbing the code inevitably helped because things started making more sense and I was able to launch an experiment with my feature just before my internship ended.

Nicholas: I was also intimated by the size of the code base when I took over the performance testing tool. I made sure to carefully test all of my changes before merging them in, and I recently decided to break the performance testing tool apart from the deployment tool. Now that the performance testing tool has become so important to us, there were many changes that needed to be made to make it reliable, customizable, and fully self-service. It was challenging to make all these large changes while keeping the service running for my team members to use; it’s hard to schedule downtime when everyone has changes they want merged! 

Most memorable experience so far?

Sunil: The time I found out that my first feature was about to be rolled into production was awesome. Right before my internship ended, I had just launched an experiment with the feature that I was developing at 20% traffic. When I joined full time, my first question to my team was, “how did it go?” And they let me know it went well. Later on, I saw the performance charts and then there was a presentation from the product team where they gave the exact million dollar effect that my feature had on revenue. That was quite memorable for me and satisfying to see the impact of my work on a large scale!

Nicholas: The holiday season is a tough time for most e-commerce companies, and the performance testing tool is very important for evaluating changes for holiday readiness. My most memorable experience was when my manager called me after Black Friday and told me that the Ranking and Personalization service was able to handle all the traffic we got as a result of my hard work. The tool allowed us to create a stable holiday readiness branch and made debugging performance issues much easier.

And finally… what drew you both to come back to Groupon as new grads?

Sunil: For me, it was really the kind of work that I had done during my internship. It was closely related to the specialization that I was pursuing in my Master’s degree. It was pretty much exactly what I wanted to do further in my career. 

Nicholas: I also enjoyed the work I did during my internship and I’m looking forward to applying some of the research I did as an undergraduate to allow for faster and more reliable performance run results. I chose to continue working at Groupon because it’s the best place for me to improve as a developer and it’s a place where I can have a large impact in my company.

Michael Janusa, Software Engineer

Michael Janusa, Software Engineer

What’s it like to be an Engineer at Groupon in Seattle? Michael Janusa, a current Software Development Engineer, talks about impact of work as well as learning from teammates. Plus, a brand new office with a stunning view doesn’t hurt.

Title: Software Development Engineer – Goods
Start date: February 2015

What brought you to Groupon? Before joining Groupon, I was working at a much larger technology company in the Seattle area where I was a bit frustrated with the slow-moving nature and low impact of the work. I started looking for opportunities in the area with smaller engineering teams where I would be able to have a larger impact and discovered the opportunity at Groupon. During my onsite interview with my team, I became very excited about joining Groupon after hearing about the various interesting, high-impact projects they were working on.

You work on the Goods team; how is the work you do impacting the Goods business? I work on the Groupon Goods logistics team, which handles the fulfillment of all of our customers’ Goods orders. We are able to have a huge impact on both the company’s performance and the overall customer experience. As a still relatively young business, there are still countless opportunities in our logistics operations to increase efficiency that leads to both cutting costs and faster delivery of orders. It is incredible how large of a financial impact a small change in our process can have due to the scale of the Goods business.

How have you grown professionally since starting at Groupon? My team at Groupon consists of some of the most talented engineers I have encountered in my career. As one of the more junior engineers on our team, I have been able to expand my engineering skills very quickly as I learn from my teammates. Groupon is also a bit unique in that engineers are tasked with a much larger project management role than is often expected of engineers so I have been able dive much deeper into the business aspects of the job and grow skills that branch outside of engineering.

How’s the new Seattle office? The new office is absolutely amazing. The building we are in is one of the tallest buildings in Seattle and a bit of an icon in the Seattle skyline. The office itself has beautiful views of Puget Sound and the Space Needle from basically every corner of the office. It’s great being able to come to such a beautiful office every day.

What’s the culture in Seattle like? We have a really tight-knit team; everyone on the team is always very open to jumping in and helping out if you’re in need or just sitting down to bounce ideas off of one another. We regularly go out to lunch together and have team events off site about once per quarter.  Our engineering culture is very fast paced and we often have multiple projects going at one time. Since our projects often have high impact on the company, there is frequently a lot of pressure to get our projects done on time, but our team manages to stay fairly relaxed in what can be a high-pressure environment.

What’s your favorite Groupon memory so far? I’ve made a lot of great memories at Groupon through various team events and engineering challenges so it is quite difficult to pick one as a favorite. I think one of the most interesting things I have done since joining Groupon was traveling to Kentucky to see our Goods Fulfillment Center. It was really exciting to see how the code we write in Seattle directly effects the operations of the warehouse as well as the people that work there.

Thanks for reading the People Blog—a blog about people at Groupon. We’re looking to add tech talent to our Engineering teams in Seattle; check out our current openings!