Jieqiong Yu on joining Mercari as a tech lead
Jieqiong shares her experience of joining Mercari and working as a tech lead. She explains their engineering culture and provides tips for potential applicants.
Jieqiong pursued a degree in computer science because she thought that coding was cool, and that it was a relatively easy career to get started with. “If I were a doctor”, she said, “I need a patient. If I don’t have enough experience, most likely patients don’t want me to work on them. As a software engineer, all I need is a computer. I can try a lot of things, and break a lot of things, and by breaking them I can learn.” This attitude of learning through experimentation would serve her well when she joined Mercari, as “Go Bold”, taking on challenges and learning from failures, is one of their core values.
Mercari is Japan’s first unicorn. Their user base expanded very quickly. I thought there must be some secret to make them so successful. I wanted to know what this was.
After graduating university, and spending several years working as a software engineer, she was contacted by a recruiter about working at Mercari. Immediately she was attracted to the company. She said, “Mercari is Japan’s first unicorn. Their user base expanded very quickly. I thought there must be some secret to make them so successful. I wanted to know what this was.”
Jieqiong was hired by Mercari, where she’s currently a tech lead. As a tech lead, she drives projects from an engineering perspective, and is responsible for technical decisions. Rather than top down decision making though, her approach is to involve the entire team. She said, “I prefer we discuss decisions with everyone, no matter their level of experience. During these discussions everyone can learn something. Even for junior engineers, maybe they didn’t know how to handle this situation by themselves, but by participating in the discussion, they might know how to handle this kind of issue next time.”
Mercari divides their organization into “camps”, each responsible for different domains. Jieqiong is part of the CRM camp. She explains, “For our camp, we’re doing things like using the user data to come up with campaigns for engagement of users. We have experimental projects, where we try something to see if it brings more users. We can try new ideas, and fail fast. This kind of thing is very interesting, and I feel excited when I’m doing this.”
Every engineer’s ideas matter. It’s not like a traditional big company, where you work on only small details. You still have the chance to do a relatively big thing.
Jieqiong thinks Mercari is at a great stage right now. “Mercari is not that small, and it’s not a startup anymore”, she said, “But at the same time, it has the startup spirit for initiatives. There are no limitations, and anything can happen here. Every engineer’s ideas matter. It’s not like a traditional big company, where you work on only small details. You still have the chance to do a relatively big thing.”
She also thinks that Mercari has an excellent engineering culture, in particular, because the culture is blameless. She said, “If someone has trouble, or there is an incident in production, it only shows that our system or process has a flaw. It’s not the individual who did the thing who is blamed.”
Mercari values the engineer’s growth. It thinks it is very important for the company’s long term growth as well.
She also appreciates the culture of learning. There’s many small clubs where people discuss and improve their technical skills together. For example, she’s part of a security championship program. She said, “For most software engineers or developers, we’re not security experts. But by participating in this program, we learn security related knowledge, and to apply it in our daily development work, to make the software more secure at the application level.”
Once a quarter, Mercari has a “hack week”, where developers can work on whatever they want to. On her last Hack Week, Jieqiong taught herself iOS development. She said, “Because I’m a backend engineer, I don’t have any experience working on mobile apps. I wanted to build chat functionality into our apps. But because I don’t have any iOS knowledge, it ended up that I spent a lot of time just learning the Swift basics.” There’s lots of opportunities like this to learn and improve your skills. “Mercari values the engineer’s growth”, she said, ”it thinks it is very important for the company’s long term growth as well”.
With COVID-19, Mercari shifted to having employees work from home from mid-February, making them one of the first major companies in Japan to do so. Jieqiong said, “By the company doing that, I feel like it values the employees health. I feel really secured by this kind of policy or decision.”
Even though we don’t care much about the candidate’s previous technical background, it does help if the person’s tech stack does match what we use now.
If you’re interested in applying for Mercari as a backend developer, Jieqiong has some specific suggestions for how you can prepare. “Even though we don’t care much about the candidate’s previous technical background”, she said, “it does help if the person’s tech stack does match what we use now. For instance, Mercari’s backend uses Golang and Google Cloud Platform. Even if the candidate doesn’t have production experience with these technologies, if he or she has some personal project using it, it would help.”
Assuming you make it past the initial screening, you’ll be asked to take an online coding test. To prepare for this, she said, “Especially for the people who are not that familiar with computer science basics, for example data structures or algorithms, I recommend them to refresh those things. They could use an online coding challenge website to practice for example.”
Once you’ve made it past the coding challenge, during the interview you’ll be asked to present a project you’ve worked on. As part of this, she said she’s looking for two main things from a technical perspective. She said, “The first one is why they made the technical decisions like that. Because by asking this, we can have a better understanding of what other tasks the candidate knows, and also if that person values why instead of just how. The other thing I ask the candidate is for a system or project he or she has worked on, is there any way that it could be improved. Because in Mercari, we have the culture to seek continuous improvement. There is no good that is too good.” So in preparation for this interview, you could choose a project you’ve worked on, and think more about why you made the technical decisions that you did.
In Mercari, it’s open, you can jump into any code repository, and ask a question, make a comment, or create a pull request. This is related to one of Mercari’s values: All for One. No matter what your role is, no matter what team you’re in, our goal is for Mercari to make better service for our end users.
Besides the technical side, she’s also looking for a culture match. She said, “We also evaluate if the person is willing to learn, and is willing to cooperate with others. Also, is he or she willing to share things? In Mercari, it’s open, you can jump into any code repository, and ask a question, make a comment, or create a pull request. This is related to one of Mercari’s values: All for One. No matter what your role is, no matter what team you’re in, our goal is for Mercari to make better service for our end users. So we don’t keep knowledge to ourselves, we share it with everyone in the company.”