In 2025, Merpay’s “Send/Receive” feature for transferring funds between individuals received its first update in five years. The update included the addition of QR-code fund transfer functionality and improvements to the flow for receiving funds, allowing users to more easily and seamlessly exchange funds for their everyday needs. 

Over the past five years, despite requests for improvements to the fund transfer feature within the company, there was a low perceived need for the feature, and we struggled to justify turning it into a project and working toward implementation.

What drove the project was the enthusiasm of a new graduate member who said, “If no one else is going to do it, let’s do it ourselves!” That sentiment combined with a dev offsite got many members involved and eventually even got leadership on board.

This bottom-up project overcame countless obstacles before finally achieving release. We spoke with the core members of the project about its trajectory and future prospects.

“Why don’t we improve this?”—a simple question from a new graduate member restarts development

—First, could you explain why Merpay’s Send/Receive feature was developed? And why hadn’t there been a major update for five years?

@phi: I didn’t join the company until 2023, so this is what I heard from the PM at the time, but there were two reasons behind the release of the Send/Receive feature in 2020.

The first was to reinforce the Mercari ecosystem. The intent was to increase the number of ways that funds generated within Mercari could be used. The second was to increase the number of users who had completed identity verification (eKYC), which was a focus area for Merpay at the time. Since identity verification is required for P2P fund transfers, the feature would also serve as a strategy to promote identity verification.

—I see. We were developing it both as a new feature for users and as a business strategy. So, why didn’t the feature receive additional updates?

@phi: Honestly, the main reason seems to have been that there was not yet a clear need for the fund transfer feature. P2P fund transfer is a form of infrastructure, so to speak, and the feature itself does not generate direct benefits. We had not fully determined how the feature would be positioned in relation to the business, and there wasn’t a clear user need for it either, making it difficult to prioritize feature improvements.

There was constant feedback from within the company as well about the feature being difficult to use, and even Mercari employees used competitors’ services for fund transfers.

@kubomi: Even when we restarted the project, identifying user needs was a big challenge for us as well. When we were asked, “To what extent will people use it?” and “What impact will it have?” it became clear that simple passion and desire to make the feature easier to use would not be enough to move the company.

—What made you all decide to move the project forward despite challenges around priority?

@phi: The new graduate members of 2023, including myself, all agreed that if no one else was going to do it, we wanted to make it happen ourselves. I experienced firsthand how much of a hassle settling the bill can be when I participated in company club activities, and @kobaryo saw a difficult-to-use P2P fund transfer feature as a fatal issue if we wanted to make Merpay a strong product.

So I gathered volunteers among the new grad members and we started the project. Fortunately, there were new grad members across QA, development, and operations, so we saw hope that our combined skillsets could make it happen. However, I didn’t have much leadership experience at that time, and it was hard to coordinate the project when each member had their actual work to do as well. But I didn’t give up, and I continued to sort through the issues and prepare for the day we could propose the project to management.

The offsite where passionate volunteers brought a prototype to life 

—How did the project team evolve into its current form from the initial group of volunteers?

@kobaryo: It was largely thanks to a dev offsite that took place in January 2025. It came at the perfect time and gave us an opportunity to fully commit to something outside of our regular work. @phi had also been sharing his ideas for feature improvements, so we decided to try fleshing them out together at the offsite.

@kubomi: From there, more and more members joined, and the team started to take shape. I joined the team in the morning on the day of the offsite after hearing about the project from @kobaryo on the way there. (laughs)

—That’s the power of passion. How did development go at the offsite?

@kobaryo: It was only two days, but we focused intensely. The backend members tried iOS development for the first time then and there, and everyone worked late into the night. Even when the presentations began, we were still coding behind the scenes.

@phi: We were even coding in the middle of the bingo tournament. I think our team was probably giving off strange vibes. (laughs)

@kobaryo: But thanks to all that effort, we were able to show a prototype video during our presentation! No other team got as far as we did in two days, and I feel like our presentation attracted quite a bit of attention. But we were only able to achieve this thanks to the thorough preparation that took place beforehand.

@phi: Yes, I learned from my past failures. As I mentioned earlier, gathering a group of passionate members is not enough if the requirements for development are not clearly defined. That led to the project naturally fizzling out, which was an extremely unfortunate experience. This time, I prepared the issues and the scope quite specifically in advance. That way, on the day of the offsite we were able to focus on just making it a reality. I think that played a major factor in us being able to complete the prototype in a short amount of time.

“It can’t end here”—hurdles to setting up the project and talks with management

—So with the success at the offsite and support from management, the idea turned into a project, then?

@kubomi: Yes. We received encouraging words that our idea was good and so we should continue to develop it after the offsite, so we said “Let us do it!” …But that was the beginning of a long journey.

@phi: When we tried to turn our idea into an project, we hit a big wall. The members were mainly young volunteers, each juggling their main work with this project. No one knew how to establish a project owner, where to secure QA and budget resources, or the formal way to proceed.

@kobaryo: We held weekly meetings, but our discussions always led to ideas for more things we could do, causing the scope to expand to the point where we almost gave up entirely. Another issue was how we would handle operations after release. We can’t just release something and hand it off to another team, saying “Here you go.”

—It sounds like you were faced with the difficulties of a bottom-up approach. How did you overcome those challenges?

@phi: We had @yag join us as a PM. From the moment he joined the project, it felt like the gears suddenly started moving again.

@yag: When I joined, I could tell that all the members were very enthusiastic, but the path forward was not clear. So I thought of my role as being the one to organize and shed light on the path that would turn their passion for developing this feature into something we could deliver to our users.

Specifically, I said that if there are limits to what we can do in a bottom-up project, we should seek top-down approval, and suggested bringing the project to the Merpay executive meeting. If we could make it an official project within the company, that would begin to resolve the issues around resources and ownership.

@kobaryo: @yag’s suggestion was truly a breakthrough. Making the project a company goal from the top down would remove blockers from various sides. Until that point, it was basically a voluntary side-project, and my manager told me to make sure I don’t let it affect my actual duties. (laughs) Thankfully, we were able to get the project officially added to the company’s roadmap. That marked a truly significant change.

“How can we create 10X the value?”—the question from high up

—Did the proposal at the executive meeting go smoothly?

@phi: One of the executive members had a stronger passion for this feature improvement than we had imagined. We were told, “Can you start working on the improvements right away?” It almost felt like we were being asked to develop the feature rather than asking for permission to do so.

@yag: That’s when we received an unforgettable piece of feedback. What we brought in was just a prototype-level idea for improvement created at an offsite. To that, we were asked, “What happens after the improvements? Think about how you can create 10X the value for our users.” 

The concept came as such a shock to me. We were only considering how we could solve immediate usability issues, but we were asked to think from a much higher vantage point about the future of the product.

@kubomi: Not only that, but we were also asked to consider things like how we would go about it in a way that is unique to Merpay, and about the significance of us doing it. Rather than simply providing similar, convenient features that competitors’ apps offer, how can we leverage Mercari’s assets to provide value that only we can offer? Thanks to these questions, our discussion deepened significantly.

We were given an important opportunity to consider the company’s mission and the fundamental value that the product offers in a way that we normally wouldn’t in our day-to-day work. I feel that this experience has raised the bar for how the team as a whole sees things.

The future of value exchange that can only be achieved by Merpay

—This project really overcame various obstacles to get to release. Did the team face any other challenges in the development phase?

@kubomi: Yes. We wanted to deliver the updates to users as quickly as possible, so on the client side, we decided to implement the updates on the old architecture without waiting for the planned migration to be completed. It took time to understand code we don’t usually touch and to verify the scope of impact, which was challenging.

@kobaryo: On the backend side, we struggled to ensure consistency of behavior across different version of the app. We needed to consider a complex combination of four cases resulting from senders and receivers who either had or hadn’t applied the updates.

@yag: Just before the release, we also discovered that we needed to address legal issues. Concerns were raised about whether the same legal conditions would apply before and after the update. It seemed as though the release was in jeopardy, but the legal team did their utmost to sort things out and found a solution. It was really a testament to the strength of Mercari’s teamwork.

—After that, the QR-code fund transfer feature was released, followed by improvements to the authorization flow. What plans do you have in store for the future?

@kobaryo: In the short term, we believe that further improvements to the UI and UX are necessary. We plan to bring the feature to up to date with the latest version of our design system and create an intuitive user experience. First and foremost, our goal is to properly provide the value of “being able to send money with Merpay,” which is not yet a widely known feature, to our users.

@kubomi: In the medium to long term, we want to achieve a broader form of “value exchange.” Mercari Group handles a variety of assets beyond money, from points to cryptoassets, NFTs, and even mobile data. If all of these forms of value could be seamlessly sent and received between individuals, we could create a completely new experience.

@phi: I want our product to be not only easy to use but fun to use. For instance, we could make it possible to transfer funds with NFC just by touching devices, or add effects like vibration (haptics) for a fun sensation as well. I want to think of ways to make the experience not just a money transaction but an enjoyable form of communication.

And the growth of the business is also important. In the future, I want to explore avenues that could make this feature one of the pillars of Merpay’s revenue.

—To conclude this interview, could you each share a word about your thoughts as you pursued this bottom-up project?

@kobaryo: Most projects are top down, so more than anything, it was truly a valuable experience to be able to take ownership and deliver a feature originating from our own desire to do so. And being asked to consider how we could create “10X the value” opened my eyes to the intriguing perspective of going back to the company vision when thinking about our work.

@yag: Personally, I was reminded of the depth of Mercari’s commitment when I saw how sincerely leadership met the passion of the engineers. It was also a great joy for me to be involved in a feature that users interact with directly, which is different from the financial area I usually handle.

@phi: Because I failed in leading the project the first time around, this was a significant learning experience for me. I can say for sure that my passion for the product is second to none, and I will use this experience as a stepping stone to take on new challenges.

@kubomi: I was able to work with the best team to actively devise and make something that we ourselves really wanted to see a reality. It was truly a great experience. Through this project, I experienced firsthand the difficulty of delivering value to users and the joy of overcoming those challenges.