From New Graduate to Tech Lead in One Year: Changes of an Engineer at Mercari

During this series of featured articles, our recruiters at Mercari will take us through some of our new graduate members’ experiences since they first joined the company. What do these new graduates, who chose Mercari as their first career, think right now, and what kind of career are they building for themselves?

After our first, second, and third featured articles, today we are meeting Ken Tominaga, who joined the company as a new graduate iOS engineer, and is now acting as a Tech Lead (TL), driving projects from an engineering perspective. Interviewing him is Ayano Okuda, from our Graduate Talent Acquisition Team.

Tominaga participated in several hackathons before joining Mercari. He increased his engineering skills, and participated in events such as Imagine Cup 2018, an IT contest organized by Microsoft, where he ranked 3rd in the world. Currently, he drives not only iOS projects, but also projects in areas like Android and frontend as a TL. How did his work and views change with this? How did his personal goals change as he assumed the role of TL? We’ll try to find out about the present of a former ordinary engineer.

Impressed by open-source contributions from Mercari’s engineers

Okuda: Before you joined Mercari, I believe you participated in several hackathons and internships, right? What made you choose Mercari?

Tominaga: I looked at several companies while I was job hunting, but I always wanted my work to be related to services my family and friends were using. At the time, Mercari was trying to grow quickly, had already released the US version of the app, and was very proactive towards expanding globally. Plus, I had heard things within the engineering community like “Mercari is a great working environment for engineers,” or “you can work with talented engineers.” I went through the selection process after contacting the company through the GitHub hiring (an application process where the candidate only sends their GitHub account and email address) they were doing at the time. I received the offer in February 2017 and joined the company in April of the following year.

Ken Tominaga (iOS engineer)

Okuda: At that time, Mercari had just begun actively hiring new graduates. The service was starting to get noticed, but the company’s name wasn’t so well known yet. Where did you hear that you could work with talented engineers?

Tominaga: I’ve been attending conferences since I was at university, and I’ve seen Mercari engineers present on stage, and contribute to open-source software (software where the source code is available for free to allow anyone to improve or redistribute it). That’s when I thought, “Mercari has really strong engineers.”

Okuda: Did you find any gaps once you joined the company, with the company culture for example?

Tominaga: I was surprised with how open information is. For example, during the training for new graduates, we would use actual data used in the real world, as opposed to sample data for discussions. Of course, it was shared because we were already employees, but I wondered if it was okay for us to see that kind of information. Also, I had the idea that Mercari was a mature company, but I realized it wasn’t so much.

Okuda: What do you mean?

Tominaga: Companies that have grown to some extent seem mature when seen from outside, and they give the impression that there’s nothing much to do there. Mercari was like that for me. But once I joined, I felt like there were still a lot of things that can be done at Mercari, not only in engineering, but also in how they take on new members, or in the onboarding for training them. That surprised me.

Finding motivation in “making users happy with my code”

Okuda: What kind of work did you do right after joining the company?

Ayano Okuda (Graduate Talent Acquisition manager)

Tominaga: When I first joined, I was assigned to the CRE (Customer Reliability Engineering) Team, which is the team in charge of ensuring our users’ safety and security through engineering. I was in charge of a feature that allows users to attach pictures when they contact us. It was a project connected with other teams, like Customer Service, but thankfully my mentor introduced me to everyone beforehand, and taught me who was the project manager, and the designer, and so on. After we released the feature, I heard there was a new project to re-architect the listing screen, so I decided to join that one.

Okuda: With re-architecture, you mean a project to rewrite the code so that the service remains stable even as we expand it, right? What made you want to join that?

Tominaga: The CRE project had just partially finished, and I thought it would be interesting to rewrite it in a new structure, so I talked directly to my manager. He made arrangements and I could start immediately. Doing the re-architecture I did different things like work with log implementations, and look for parts of the pre-existing code that could be improved. It was really, really fun. According to other project members I would say things like “Quickly! Review my best code ever!” (laughs). My results during that time were acknowledged, and I received the Go Bold Award, one of the MVP awards at the company.

Okuda: You must have felt really happy! Were you surprised?

Tominaga: Actually, the day before, my manager at the time, Tagaya (Engineering Office Director), asked me if I was going to attend the all-hands meeting the next day. And, to be honest, I thought that something was going to happen. I had just come out 3rd in the world at the Imagine Cup, the IT contest organized by Microsoft, so I thought that surely he was going to make a comment about it. Little did I know it was about the Go Bold award…

Okuda: You must have been really happy. And did you go back to CRE after finishing the re-architecture project?

Tominaga: After finishing the re-architecture project, I joined the NPS (Net Promoter Score) team, where we worked on a project to improve the contact guidelines, and simplify the process for the users.

Okuda: Okay, so re-architecture with CRE, and then NPS. It seems like you are involved in a lot of features related to our users, right?

Tominaga: I guess so. That’s because my motivation is to make users happy with my code, so I would openly discuss with the product manager if what we were doing was actually good for the users or not, no matter what project it was. I particularly remember that one time when I was at CRE, one of the members from Customer Service said it was great for them to be able to see the pictures when supporting users. That feedback made me really happy.


Perspective changes: from engineer to Tech Lead

Okuda: So you’ve been working as a TL since January this year. How does that affect your career?

Tominaga: Rather than being interested in becoming a manager, I always felt that a more technical role like TL would better fit my career. And I expressed that to my manager. So, when I was appointed TL, I felt that the company was giving me a bigger responsibility, while acknowledging the work I had been doing until then.

Okuda: Participating in the Imagine Cup and all, it seems to me that you are very proactive towards improving your skills. But I guess that now that you are a TL, you probably don’t have much time to write code, do you?

Tominaga: The role of a TL is to drive projects from an engineering point of view. It’s important to not only handle technical problems that arise, but also to eliminate risks before they happen. I consciously reduced my time writing code because of this. There are meetings between TLs from all over Mercari Group, and some of them had already told me things like “it’s a shame we have less time to write code, but on the other hand, we can be involved in decision-making,” so the gap wasn’t as big as I thought.


Okuda: Did the way you work change in any way?

Tominaga: Mostly, the way I use my time. Up until then, I would spend all my time writing code (laughs). But since I became a TL, I have to make decisions regarding the whole project, and track the progress. Also, now I have a lot more meetings where we make technical decisions for the Group, so I have less time not only to do tasks, but also to communicate with the team members that I’m mentoring. Right now I’m working this out by blocking my calendar so that I don’t get new appointments, and intentionally making time to be at my desk.

Okuda: Given that you have less time to write code, do you feel that you learned other things or skills?

Tominaga: Before, I was focused on writing code, but now, as a TL, I am more in contact with engineering managers, so I feel that I have a broader perspective. I have a new way of looking at things now, since I need to think about things like what kind of technologies are necessary to run our mid- and long-term projects, or what kind of team structure we should have. TLs also need to maintain the team members’ motivation. In my case, I haven’t been able to make the team work well together. That’s something I still need to work on.


Okuda: As someone who became a recruiting manager myself, I feel that the more the organization grows, the more difficult it gets to keep up with new information. How do you feel about this?

Tominaga: Oh, it happens. Mercari still has a high level of transparency regarding information. It depends on us whether we can maintain that or not in the future. That’s why it’s really important for us to think not only about the different teams, but also about the different projects.

I learned to delegate after joining Mercari

Okuda: Do you feel you’ve personally changed after you joined Mercari?

Tominaga: I think I became more careful towards engineering, and also learned to delegate more to other people. Before joining I was doing an internship at a startup, and back then, the most important thing was to carry on with the projects. Of course, this is also important at Mercari, but we have a lot of people using our service now. For them to continue using our app, we have to go bold and challenge new features, but at the same time, in engineering, we need to write tests and always keep safety and security in mind.

Okuda: What do you mean by delegating to other people?

Tominaga: Until now, I used to think that if there was something I could do, I should just do it. However, now that I’m a mentor and a TL, I realized that we can make faster progress on our projects if I delegate tasks to other members and then offer them my support. Plus, that way our work is not so overly reliant on individuals, and it’s easier to scale our service. Although, there are still times when I feel like I want to do things by myself.


Okuda: Is there anything you want to try in the future?

Tominaga: I specialize in iOS, but since now I became a TL, I’d like to strengthen my knowledge in backend and security, in addition to Android and frontend. Also, I’m now focusing on Mercari, but I would like to challenge myself at Merpay or Mercari US. Eventually I want to start my own business, so I want to use all the experience I can gather in Mercari to make the best code and the best product I can.

Ken Tominaga

After entering university, started developing iOS applications, and has participated in several hackathons and internships. His main achievement was to come third in the world at the Imagine Cup 2018. Joined Mercari in April 2018 after graduation. After gaining experience in CRE and NPS teams, he is currently Tech Lead for the Car project.

Ayano Okuda

Joined CyberAgent, Inc. in 2009. After being assigned to the president’s office, she gained experience in planning, operation, and progress management as a social game producer. Later, she also gained experience in business strategy and management as a Unit Leader, handling several games. Joined Mercari in March 2017, and is now involved in graduate talent acquisition.

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