Senior Backend Engineer

Tokyo
Remote OK - Anywhere in Japan
Full-time
May 30, 2025

About KOMOJU

KOMOJU (by Degica) is the leading cross-border payment gateway for Japan. We power payments for companies like video game distribution platform Steam and the popular mobile app TikTok. Today we help thousands of merchants by providing them with the payment infrastructure they need through developer-friendly API’s to integrations on popular platforms like Shopify and Wix; we help our merchants grow in all markets they are expanding.

What to expect

We are product focused, meaning you will work on our payment gateway and any other projects towards building the future of KOMOJU. You will work with other engineers in a flat and inclusive culture where engineers have a say in both key product and technology decisions. The culture is largely self-organizing, which means engineers have both a stake and ownership in what they work on. Engineers play to their strengths, but are also able to invest in areas where they want to grow within the team. At KOMOJU, you are the main driver behind your growth and position in the company.

International at our core

Around half of our team members come from outside Japan. English is the primary language used within our engineering team, and throughout the company, many people are bilingual.

Being an international company we know the importance of bilingualism. We offer all employees a choice between optional English and Japanese lessons to help create a culture of diversity and ensure smooth collaboration across teams.

About the position

We are looking for a senior backend engineer to help up build our platform to handle payments on a global scale. You will primarily work with Ruby, building out features using Ruby on Rails. As we’re still scaling our front-end team, you may be asked occasionally to work on front-end tasks as well.

As a senior engineer, you will need to work with our product managers to define requirements and convert that into a usable architecture, and then implement them in code. You will also provide constructive feedback through code reviews, as well as architecture discussions. As hiring and supporting new developers is important to us, you will be expected to be able to mentor junior developers, and work with them to improve their core skills.

Our ideal candidate has experience working with large web applications. They will know how to build reliable, scalable, and performant web applications. Testing and code quality are also extremely important to us, so having a strong knowledge of testing and the different testing types is required.

Responsibilities

Build backend systems using Ruby on Rails stack
Understand product goals and feature requests and translate them into working software
Lead large technical projects from design through implementation and delivery
Support team members through code review and architecture discussions
Ensure high-quality, reliable software - including thorough testing, proactive monitoring, observability, and continuous improvement
Identify high-leverage refactoring opportunities that improve team velocity, code clarity, and long-term maintainability

Requirements

Experience with building performant and scalable APIs
Solid understanding of database performance characteristics and data access patterns
Ability to design data models and system architectures spanning multiple data stores (experience working with OLAP and OLTP databases)
Hands-on experience with observability practices, including metrics, logging and tracing
Strong technical communication skills - including the ability to document designs and decisions clearly and concisely
Experience with integrating with third party APIs in a secure and fault-tolerant manner
Experience and understanding of common web vulnerabilities and how to mitigate them
Strong understanding of software architecture, design patterns and best practices

Nice to Haves

These aren't required, but be sure to mention them in your application if you have them.

Experience with TypeScript, Vue.js and/or React
Experience with payments or payment systems
Business-level spoken Japanese

*We’re hiring for multiple openings across different seniority levels. The final title and scope of responsibilities will be determined based on your experience and performance throughout the interview process.

Benefits

At Degica, we embrace remote work while also offering office space for those who prefer in-person collaboration
10 days regular vacation, additional 5 days summer and 5 days winter vacation
Paid birthday holiday
Budget for self-learning allowance, to ensure our employees’ skills remain current
Language training for Japanese

APPLY NOW ➜

About KOMOJU

KOMOJU (by Degica) is the leading cross-border payment gateway for Japan.

We power payments for companies like video game distribution platform Steam and the popular mobile app TikTok.

Today we help thousands of merchants by providing them with the payment infrastructure they need, through developer-friendly API’s to integrations on popular platforms like Shopify and Wix; we help our merchants grow in all markets they are expanding.

When it comes to engineering, we believe in having a flat, inclusive culture and constantly improving by continuing to evaluate ourselves. We also prize individuality and believe that each member brings their own unique value to the team.

Our development processes are always updating as the company grows, and we have an engineering culture that largely organizes itself and each engineer has a lot of ownership in their own projects. This culture allows engineers to showcase their strengths while continuing to grow.

Japanese Language Policy
With around half of their total members (and around 75% of engineers) coming from outside Japan, KOMOJU generally uses English for written communication (e.g. Slack, Github). Verbal communication is also primarily in English.

However, quite a few people working there can speak both English and Japanese fluently so Japanese may be spoken at times during meetings, especially when they involve teams other than engineering.

Overall, the language spoken depends on the team. The dev team uses mostly English, but their HR team (for example) speaks primarily Japanese.
Visa Sponsorship
KOMOJU sponsors visas for candidates living outside of Japan. They’re still hiring from abroad, but due to travel restrictions related to COVID-19 new employees from abroad may need to start working on a contract basis. KOMOJU will switch you over to a full-time employee contract and sponsor your visa once it’s safe to come to Japan again.

KOMOJU also helps out with relocation (searching for apartments etc.) but they don’t have a formal policy for this. The support offered depends on each individual case. They do always pay for flight tickets to Japan in the case that someone moves from abroad however.
Paid Leave
KOMOJU has a very generous vacation policy.

Like most companies in Japan, their basic PTO package starts with 10 days of normal paid time off during an employee’s first year, followed by increases in subsequent years in accordance with Japanese labor law.

KOMOJU also offers 5 extra vacation days that can be used during the summer months, and another 5 days of year-end holidays.

They also have birthday leave, which means members can get an extra day off each year on their birthday. So that’s a total of 21 vacation days per year in addition to Japanese public holidays. They also offer maternity and paternity leave.
Benefits
💻 New tech gear

👩‍🎓 Skill development support

💛 Support for attending conferences

🧡 Seminar participation support

📕 Book purchases

👶 Parental Leave

👩‍🏫 Language Learning Support

💜 Social security / insurance benefits included

🏥 Healthcare insurance

💚 Pension insurance

🚃 Commuter allowance

👍 Motorized sitting / standing desks when working from our office
Engineer Interview Process
Engineering Jobs

KOMOJU’s interview process skips the high-pressure whiteboard interviews in favor of a coding challenge that’s closer to what engineers would actually work on day-to-day.

Here’s the basic interview flow:
- First interview: Meeting with two KOMOJU engineers to discuss about something you’ve built and see if you’re a good cultural fit
- Second interview: Technical challenge to test your real-world development skills
- Third interview: Meeting with a senior leader in the company
Remote Work
KOMOJU allows full remote work from anywhere in the world! The only stipulation is that your work hours must have some overlap with the JST time zone.

Even once COVID-19 is no longer a concern, KOMOJU intends to continue their full remote policy.

And if you do relocate to Japan, there's no need to live near their Tokyo office — you can work from anywhere in Japan.
Work style
KOMOJU has an office in the Kichijoji area of Tokyo, but they’ve switched to working fully remotely due to COVID-19. A typical work day at KOMOJU begins at around 10:00AM for most people. Some teams begin with a stand-up meeting where they quickly share their tasks for the day before focusing on work for the rest of the day.

One unique aspect of KOMOJU’s work style is their code review process. Since they have a flat hierarchy and a relatively small team, they have a system where reviewers are selected randomly. Their engineers also take care of operations and handle errors or technical customer queries as a team via Slack.

A typical stopping time for engineers at KOMOJU is at around 7:00PM, and they have very little overtime so engineers normally won’t be online past this time. They also make it a point to avoid unnecessary meetings and prefer to have ad-hoc discussions with relevant members only.