The Approach to Quality for Frontend Teams at Merpay and Mercoin #WorkWithMerpay

In our job postings, you can find things like our minimum and preferred requirements, or our ideal candidate…But, what does that mean, exactly?

#WorkWithMerpay is a new series of articles where our recruiters talk with managers from different teams to delve into what kind of person they’re looking for! In this edition we will showcase Merpay Frontend Engineer Yutaro Tanaka (@tanawa) and Mercoin Frontend Engineer Margaux Flores (@margaux).

We asked about their main responsibilities on the Frontend Team and their respective careers. Read on to learn more about the skills needed for developing financial and payment services! Interview conducted by Momoko Matsuka (Merpay HRBP, @momoka).

Featured in this article


  • Yutaro Tanaka, @tanawa

    Joined Merpay as a Frontend Engineer in August 2018. As a TL, worked on areas including improving efficiency of merchant screenings, microservice partitioning, and test automation. Became an Engineering Manager in October 2020.


  • Margaux Flores, @margaux

    Joined Mercoin in June 2021. Currently works on frontend development for new products at Mercoin.


Aligned with Individual Members’ Interests

—To start off, please tell us about the main responsibilities of the Frontend Teams at Merpay and Mercoin, respectively.

@tanawa: The Merpay Frontend Team works on development of web components. Most would think that frontend engineers work on native app development. However, we have a separate team in charge of native development for iOS and Android. The Merpay Frontend Team develops the web components. Our team works on three main types of products.

@tanawa: These can be broken down into products respectively for customers, for merchants, and for internal use. Customer-oriented products include campaign and coupon pages. For merchants, we develop the registration form for getting set up on the app and the dashboard for managing sales revenue after completing registration.

In terms of internal-use products, we work on the internal customer support tool used for assisting Merpay customers, as well as the merchant support tool for assisting merchants.

Yutaro Tanaka (@tanawa)

@margaux: I am a member of Mercoin, which was established in April 2021 with the goal of planning and developing services related to cryptoassets and blockchain technologies.

On the Mercoin Frontend Team, we are currently working on the development of new customer-oriented services and internal tools related to cryptoassets and blockchain.

A big difference from Merpay is that we get to work with cryptoassets and blockchain. At Mercoin we are exploring various projects to make cryptoassets and blockchain, which are still fairly new for many people, accessible and easy to use for the average customer.

Margaux Flores (@margaux)

—How do Mercoin teams decide project assignments?

@tanawa: We have all different kinds of projects at Merpay and Mercoin, with relative priority changing on a regular basis. When deciding project assignments, we do our best to coordinate so that each individual can work on something that aligns with their interests.

Engineers each have their own strengths and weaknesses, as well as areas where they want to improve. Each project offers different opportunities for growth. We try our best to assign members to projects where they can gain experience that matches their interests.

@margaux: Just as @tanawa said, I believe that one of the great aspects of engineering teams at Mercari Group is this flexibility to take into account your interests when selecting a project to join. Being able to choose what you work on means you can design your own career path, which is a great way to achieve your goals. “I also think this is a great way to keep engineers motivated and excited in working on new projects within the company.”?

A Comfortable Working Environment for Everyone

—Tell us more about the Merpay and Mercoin Frontend Teams from your perspective as an engineering manager.

@tanawa: Not to brag, but we have quite the friendly team culture. Despite remote work making it difficult to talk directly, face-to-face, we are still able to solve any challenges we face by speaking openly with one another.

And for Mercari Group as a whole, we are also focused on creating a welcoming environment that can accommodate a diverse range of engineers. Currently about 40% of engineers at Mercari are actually from countries outside of Japan. We are also working to bring in more engineers from overseas to Merpay, as well. The Frontend Team has been focusing over the last year and a half on creating the right environment to take in new members from around the world.

Currently, 3 out of 14 frontend engineers are from overseas. Japanese members work on their English while the members without Japanese language ability study Japanese. We all work hard to make sure we’re communicating in our development work.

@margaux: Some of the Frontend Team members from overseas do not speak Japanese very well. As a non-Japanese member, I am very grateful that the Japanese members do their best to communicate with us in English. I actually just joined Mercoin in June 2021 myself, so I still have quite a lot to learn! Nonetheless, I feel comfortable in this friendly environment where I can ask my team members any questions I may have.

—Did anything surprise you after joining Merpay and Mercoin?

@margaux: I was amazed at the sheer number of frontend engineers. At my past jobs, I was usually the only frontend engineer, so I was quite surprised to see how many we have here. (laughs) I’d also say the culture is more flexible than I first expected. Comparing Mercari Group’s culture with other Japanese companies, I was surprised by the degree of freedom we are given.

@tanawa: I joined three years ago, and I was pleasantly surprised to see there are also many talented members in non-engineering roles. Given Mercari Group’s reputation as a tech company, seeing so many highly skilled engineers was no surprise at all. But the non-engineering members are just as talented.

On the other hand, while I expected things to be quite well developed and organized considering how big the organization has become, we still have quite a lot of room to improve. We may have a large number of employees, but we are by no means a typical large-scale corporation. In that sense, I’d say there were both positive and negative surprises.

—Can you tell us about the career paths available to frontend engineers at Merpay and Mercoin?

Momoka Matsuka (@momoka)

@tanawa: There are three main paths, for not just frontend but engineers in general: Individual Contributor (IC), Tech Lead (TL), and Engineering Manager (EM). An IC can be thought of as someone who writes code and is aiming to specialize as an engineer.

A TL takes ownership over the How, What, and When of projects. They will work together with product managers to decide what kind of product to make, by when, and how. A TL does have opportunities to write code, but at the same time they must ensure that the project runs smoothly.

An EM is in charge of the Who, Where, and How of the organization. This role entails thinking about people and the kind of work they will do, which includes project assignments as I mentioned earlier.

Generally speaking, each engineer is able to choose from these three career paths. And separate from these roles, we have a job rotation system at Merpay, through which a frontend engineer can switch to a mainly backend role. We’ve even had people switch from an iOS to backend career path.

The Engineering Ladder describes the skills and behaviors expected of engineers, and serves as a tool for setting career goals.

Merpay and Mercoin’s Approach to Quality

—What is particularly challenging about developing financial and payment services? Are there any specific skills required?

@tanawa: Working on financial and payment services does not necessarily mean you have to be an expert on payments and finance. Of course our work does require looking over specifications unique to financial services, but you can learn about these topics while working on development.

We place more focus on maintaining and improving quality than you might see with typical services.

Financial and payment services handle actual money; our work must be of sufficient quality to provide a safe experience for our customers. Nobody would want to use a payment service that is full of bugs. Therefore, not just the Frontend Team, but all of us at Merpay place great emphasis on maintaining and improving quality.

@margaux: I think focusing on security is very important. Most people would think that because we’re only developing the frontend, we don’t have to worry that much about security, but I believe that frontend security is our first line of defense in making sure that we have a secure application—especially since we’re dealing with financial and payment services.

@tanawa: Quality is a very broad term. In more concrete terms, the Frontend Team focuses on four areas: accessibility, testing, web performance, and security. We have put together various mechanisms for maintaining and making continuous improvements to quality in these four areas.

More specifically, we have developed a platform for numerically tracking these areas. We use the dashboard Looker to visualize web application performance.

@tanawa: We’ve put together a platform where we can check this visualized information in order to decide what areas need improvement. Making improvements like these requires ongoing efforts, so this kind of approach is crucial.

—Are there any differences in the skills required for working at Merpay and Mercoin?

@tanawa: Generally speaking, no. While at Mercoin we do develop services related to cryptoassets and blockchain, frontend engineers don’t currently have many opportunities to work directly with the blockchain technology. That being said, I think it’s a great place to work for those with interest in these areas.

@margaux: Compared to cashless payment services, cryptoassets and blockchain are not as familiar to the general public. This presents us with the challenge of exploring how we can use this technology to contribute to our customers’ daily lives.. Working here definitely requires an interest in this kind of challenge, but overall I would say there is no big difference in required skill sets between the two companies.

Focus on the Customer

—What kind of people would be a good fit for the Merpay and Mercoin frontend teams?

@margaux: For both companies, I would definitely say people that are always looking to take on new challenges would be a good fit. New technologies will always continue to emerge. That’s why we think that Merpay and Mercoin are the perfect companies for anyone who wants to challenge themselves in new areas.

Another thing I would mention is because the frontend teams here are so diverse and transparent, it’s a great place to work for those who are open to sharing their own opinions. We might not always agree with each other, but these differences of opinion can provide great learning opportunities. Other than that, those with a drive to continuously improve the quality of our work would be a good fit as well. I would recommend working here if you are passionate about constantly striving to improve our product.

@tanawa: I would say someone who is proactive and able to think about what kind of changes need to be made. You will rarely receive a direct order from a supervisor or fellow employee here at Merpay or Mercoin. You have to be able to think about what you want to work on and actually take the initiative.

—What does the Frontend Team focus on in the interview process?

@tanawa: Our biggest focus is a shared belief in our mission and values. Of course we look at technical skills and expertise for hiring engineers, but even more importantly, it’s crucial that the individual has a shared belief in our mission, “Building trust for a seamless society,” and our values of Go Bold, All for One, and Be a Pro.

All members within Mercari Group share a common understanding and awareness of the values, to the point that you hear them come up in daily conversation. These values are actually the foundation for evaluations as well. Even with great technical skills, those that don’t have a shared belief in the mission and values may struggle to perform to their best here.

@margaux: I personally want to work with engineers who have a drive to make a great product. If you are able to look at something from the customer’s perspective and think deeply about what really makes a great product, I believe that your way of thinking as an engineer and the quality of your code will naturally improve.

@tanawa: Our Engineering Ladder has a section called Focus on the Customer, which describes the importance of how the services and features you are developing will impact customers. This ability to actually think about the customer, and not only the development process of the feature, is a crucial skill.

If any of this work inspires you, now is the time to apply!

—How would you describe the current phase we are in at Merpay and Mercoin?

@tanawa: It’s been almost three years since we released the Merpay service. We’re currently working on strengthening our foundation for operations. Maintaining and improving quality, as I mentioned before, become even more important in this phase.

@margaux: Mercoin was just recently established, so we are focused on developing new services. We don’t really have any operations work. Although we are working on new development, we do think about early strategies we can take to maintain and improve quality.

—And to close, please share a message for any future applicants!

@tanawa: If you’re interested in maintaining and improving quality, please do apply! We’ve spent the last year or so building a platform for maintaining quality, but are just getting started on the improvement aspect. Improving quality definitely has lots of challenges. If you have any interest at all in this kind of work, feel free to reach out—even for just a casual meeting!

@margaux: Mercoin is a great environment for those interested in cryptoassets and blockchain, who want to develop new services while also maintaining and improving quality. Please feel free to reach out if you’re interested in this kind of a position!

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