Building Things That Didn’t Exist Before: Mercari’s Corporate Engineering Solutions Team Takes on Key Company Issues

The Corporate Solutions Engineering (CSE) Team was founded in January 2018 with a clear mission: Solving management issues through engineering.

CSE has developed strong and stable systems from scratch to tackle four domains: Member evaluations, accounting, media, and communication tools. This team bears the huge responsibility of supporting and strengthening Mercari’s corporate side.

CSE is a vital team that responds to the company’s needs and provides it with new value. 1 year has passed since the team’s birth, so we checked in to see how they’re doing and what they’re working on now. We interviewed 4 members from CSE’s People Products Team: wadatch (manager), fivestar (engineer), into, and funassy (Product Managers, or PMs). These members took a look back on the hard work they went through to build services and tools that didn’t exist before.

The essence of solving management issues through engineering

– I’d like to start by saying congratulations! It’s been a year since the CSE Team’s birth!

Everyone: Thank you!

– During the interview we had 1 year ago, we heard the story behind how the team started, and the goals that were set. Today, I’d like to take some time with everyone to look back on everything that’s happened since then. Can I start by asking for your honest thoughts?

wadatch: To put it bluntly, it was a super chaotic year (laughs). The time flew by, but so many things were happening every day. CSE was established in January 2018 and immediately was assigned to develop Reviews, the member evaluation system. We then developed Teams, a database of members and divisions, along with Benefits, a management system for company incentives. We had to work with several teams across the entire organization in order to create these independent systems.

wadatch(Corporate Solutions Engineering Team Manager)

fivestar: A lot happened in the past year, and at the same time, some things didn’t actually change much. I mentioned this when the team started up, but we’re just a team that develops new systems. We’re a team that uses engineering to solve management issues. This stance has not changed one bit since the day we were founded. Even when we finish building systems or features, we have to consider questions like “is this really what we needed?” and “is this actually related to the management issues at hand?” Keeping these key points in mind helped us continuously improve as a team.

– How did the team and its scope of work change over time?

wadatch: After the team was founded with sotarok (former CSE manager Sotaro Karasawa) and fivestar, we quickly realised that such a small team would not be able to handle the work involved. Benefits began as a development project in around July 2018, and we found that the team at the time wasn’t able to get everything done. That’s when into and funassy joined. That was the point when our team started to get more diverse.

into: I joined the company in July 2018. That was a time when engineering was needed to make the incentive system a reality. We figured out the requirements and started development, but the system suddenly changed at the end of October. A decision was made to start operating the system before the end of the year. The project teams and management were making very bold decisions in order to create a better system, and that was one of the first moments that made me think, “so this is Mercari!” We were polishing Reviews at the time, only to find the evaluation system going through some major changes. When I look back, it was a busy time full of unexpected events and surprises.

into(Corporate Solutions Engineering Team PM)

– You joined the company at quite an interesting time. Building new systems while maintaining Mercari’s speed definitely doesn’t sound easy. What did you have to keep in mind as you took on those challenges?

into: As you said, the speed was ridiculous and there were so many tasks coming from different places. We had to keep in mind the fact that system development is just one method of solving problems.

– What do you mean by that?

into: We discussed topics like ”What exactly is the task at hand?” and “What solutions can we think of to address those?” and “Are there any solutions that don’t involve developing systems?” Through these discussions, we decided that in-house systems were the answer. Our team excels at delivering these in-house solutions regardless of the necessary speed, and at considering the roots of the issues we aimed to solve.

funassy: into and I joined at the same time, so I totally agree with the points he brought up. The management issues we tackled required some drastic measures that would involve the entire company. This called for a lot of physical stamina as well as mental preparation.

– Company-wide issues should be made known to everyone – not just CSE, right?

funassy: Right. We have to think of ways to ensure everyone in the company is aware of the issues. The key to this is working together with the management. They’re the ones who came up with the idea of “solving management issues using technology.” Since the managers had that goal in mind, it allowed us to get the whole company involved while building new systems.

funassy(Corporate Solutions Engineering Team PM)

– Do you have any examples?

fivestar: Koizumi (Mercari COO) wanted strong evaluation system and said, “We want an organization that’s about more than just products and services. We want one that’s about the entire company. That’s why we need to think about the organization and evaluate members properly.” Koizumi’s backing is what supported us and helped us develop Reviews.

– So the management’s requests led to the creation of Reviews, Benefits, and Teams – systems that make work better for members. Why did you choose to make your own tools instead of using existing ones?

fivestar: Teams in the company work on countless different projects moving at incredible speeds. While this happens, the organization and teams still change constantly. There just aren’t any tools out there that are a good fit for Mercari, which is changing and growing in its own unique way. Unique companies need unique solutions. The speed at which we build systems has to match or surpass the speed of the company’s growth. This is why CSE makes in-house services, and I think it means a lot.

wadatch: That’s right. It’s not really about whether the solutions are in-house or external. What matters is that we think about whether or not we’re providing the best solutions.

– I see.

fivestar: CSE wasn’t formed to build in-house systems. It was formed to solve management issues through engineering. This requires us to proactively take on all kinds of challenges rather than just passively doing what we’re told. It also means we need to establish a unique brand for ourselves as Mercari CSE. I think that our past year was a success in those aspects, as we delivered significant output and established our roles in the company. Our members performed well and developed healthy mindsets. We’ve had members choose to join the company because of their interest in CSE, which helps us realize how much we’ve accomplished.

fivestar(Corporate Solutions Engineering Team Engineer)

The benefits of being respectful, open, global, and diverse

– A diverse group of members has joined the CSE Team since it was established a year ago. Can you tell us more about the team’s culture?

wadatch:Our team really emphasizes good communication. We came up with 3 values when the team started up: Respectful, Open, and Global & Diverse. These were the policies we stuck to during our daily work. Six months after the team was founded, we suddenly had an increase in members. With people coming from several different countries, our work environment became a mix of English and Japanese. This inevitably brought some challenges, but we’ve been able to communicate smoothly and get things done because everyone shares the team values.

– It’s great that your team came up with its own values in addition to the Mercari values (Go Bold, All for One, Be a Pro). I think these are important for other teams to keep in mind as well.

wadatch: Thanks to the original members sotarok and fivestar who helped set these values, we’ve been able to stay positive and find solutions even when we have serious discussions or disagreements.


– When teams grow in size, or when there are lots of members coming from different backgrounds, it’s easy to get lazy and think things like “my understanding is good enough.”

wadatch: That’s exactly what happens. There’s no way each member can have a full understanding of each others’ skills, so frequent confirmation is important. Our aim was to stop accepting things silently and without hesitation. Instead, we made sure to have the team gather regularly in order to share things and check for mutual understanding. I think those were important in developing the team’s culture.

funassy: There might be times or places when silent and unhesitant agreement are good, but it doesn’t work well for us. Some people have conversations that make sense only to them and no one else, and during those times we say “that’s too high-context!” It’s kind of become an inside joke (laughs).

wadatch: True (laughs).

fivestar: Communication problems are another type of management issue that we’re dealing with, and one of the reasons our team established its values. Sometimes the problem lies in members’ mindsets. I think that everyone needs to have a strong understanding of the team and company’s culture.


– It seems like the CSE Team’s communications skills really come in handy when working on projects with other teams.

into: Yes. Different teams work together on certain projects, and we’re the team that’s asked to solve certain problems. If someone asks us, “hey, can you make this feature for us?” then I start by asking them, “Why is that feature needed?” in order to get the necessary background information. I might be able to get a general idea by myself, but it never hurts to ask and confirm. And as we mentioned earlier, developing features is just one way to solve an issue. If people don’t explain what problems they’re facing, then we can’t propose solutions. No matter what team we’re working with or what project we’re working on, we never settle with a “good enough” understanding of the situation.


funassy: If we can solve an issue without building anything, that’s a success. That’s why we don’t focus solely on building things. If we make something, we have to maintain and operate it afterwards, and also establish a new set of unique rules. All of our team members are professionals who give their best efforts on a daily basis, thinking about the “why” and proposing new solutions with or without engineering.

Our goal: Building things that didn’t exist before

– I’d like to change the topic a bit and talk about CSE’s goals. What do you mean when you say “solve management issues?” As a team that has developed and launched several systems, what were some moments when you realized that you had successfully solved an issue?

wadatch: Our goal was to launch systems that didn’t exist before, and to have them become regular parts of our daily work. Teams and Reviews are now well-established and regularly used – everyone knows what they’re for. Everytime someone uses Teams, they’re using it for some specific purpose. That’s one way we can label the issue as “solved.” Every member has their own reason to use the tool, and we’re really happy as the team that developed it.

– Did members give you any unexpected feedback, ideas, or reactions?

funassy: Yeah, a lot. We got a suggestion for Teams – someone said we should make it possible to go from Teams directly to a user’s Slack profile. We asked them why such a feature would be necessary, and they said, “after I check someone’s calendar on Teams, I might want to send them a message.” That makes sense! When we check someone’s schedule on Teams, there’s a good chance that it’s because we’re trying to contact them. Having a link directly to Slack would be helpful in those cases. Moments like that help us remember that we’re not just building things for the sake of visualization – we’re making things that are real and functional. That’s just one of many examples, but we’ve taken a lot of ideas from members and implemented them.


fivestar: This might sound obvious, but it’s really great that we sit right next to our end users (laughs). We get feedback regularly and naturally, and that one of the great aspects of Mercari’s culture.

Success after success: CSE aims to take on the world

– Lastly, could I ask each of you to tell me about CSE’s future?

fivestar: In the past year, we built fundamental systems for the People Products Team, but we want them to be used even more throughout the company. We want to make information bases that will help Mercari’s members work at their full potential. As a backend architect myself, I’d like to focus on making systems that utilize data. I think it would lead to major advancements for both the team and the company.

wadatch: Thinking in the mid-term and long-term, I’d like to share examples of our work outside of the company as well. Even though People Products is far from being complete, we’ve already had several success stories. I think it’s unfortunate and even dangerous that internal IT departments often take on a very passive role. I think that by delivering many successful examples of proactive work, we can make changes in the whole industry. I’d also like Mercari CSE to make an impact on a global scale as part of a tech company.


– funassy and into, how about you?

funassy: I want to put my efforts into personnel and talent management. As fivestar mentioned, utilizing data effectively will be one of our major focus points in the future. We want to manage data history, leverage APIs, and make it possible for all teams to freely use the data they need. That’s our goal for the next year.

into: I want to focus on the “People” aspect while creating new mechanisms for CSE. There are a ton of management and organization issues, and the number of challenges will only go up as we get more people and physical locations. I hope that we can respond to everyone’s voices and deliver solutions that are helpful to them. And as the others said, I want to focus on data as well. We’ve gathered a lot of data on the “People” domain, which we should use to support members’ growth and careers. I want to work on these challenges both on my own and as a team.




Corporate Solutions Engineering Team Manager. Worked for SRA, Inc. and joined GREE, Inc. in 2006 where he developed and operated internal systems along with payment and advertising systems. He then joined XICA Co., Ltd. and worked as a freelancer, before joining Mercari in January 2018. He currently manages development and operations for People Products, Accounting Products, and the corporate website.


Corporate Solutions Engineering Team Engineer. Joined Asial Corp. in 2008, founded Crosos, Inc. in 2011, and sold it to Yahoo in the following year. He worked on Yahoo’s media platforms and was responsible for establishing technical strategies. In 2015, he became CTO for Ancar, Inc. He then joined Mercari in January 2018, and now works as a backend architect for People Products Team.


Corporate Solutions Engineering Team PM. Joined NTT Communications in 2010, where he planned new services and businesses. He joined Globis, Inc. in 2013 to develop digital content and plan & develop learning platforms. He then joined Mercari in July 2018, and currently works as a product manager for People Products, focusing on the evaluation system Reviews, and the RSU management system Benefits.


Corporate Solutions Engineering Team PM. Joined Mixi, Inc. in 2011 as a new grad. Worked on ad placement management for a newly established ad tech team and for game apps delivered domestically and abroad. He also worked on expanding the business into China. He joined Mercari in July 2018, working as a product manager for CSE’s People Products Team.

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