In this role, you will be primarily focused on our flagship technical assessment product used by hundreds of enterprise clients across Japan. This means both delivering new product value for our customers and tackling meaningful technical challenges: improving the architecture, reducing tech debt, and making the platform easier to extend and build upon for years to come. Our backend stack includes both TypeScript and Scala — you don’t need to know both, but you must be open to working across both day-to-day. You’ll be working in a large, mature codebase with real technical debt — we’re looking for someone who sees that as a challenge, not a red flag.
Tech Stack
- Backend: Scala (Play Framework), TypeScript (NestJS)
- Frontend: React, TypeScript
- Database: PostgreSQL, Redis
- Infrastructure: AWS, Docker, Terraform
- Tools: CircleCI · GitHub Actions, Datadog, pnpm
PC Spec
Mac or Windows - You can pick your machine from the available options.
Who fits us
- Passionate about developing SaaS products.
- Able to work diligently on continuous improvements with future operations in mind.
- Value communication with other developers and collaborate to plan schedules and engage in team development.
Responsibilities
- Take end-to-end ownership of features — from architecture decisions and implementation through testing and deployment. You’ll be expected to drive work independently and see it through to production.
- Develop and maintain backend systems across the Assessment Platform Team’s product portfolio, working primarily with Scala and TypeScript. While full-stack contributions are welcome, the core focus of this role is backend development.
- Architect and extend features across multiple products, navigating both a large-scale legacy codebase and a modern greenfield service — each with their own technical challenges and opportunities.
- Collaborate with a diverse, distributed engineering team to evaluate and clarify product requirements, and deliver technical solutions that align with user needs.
- Uphold a high-quality code base through automated testing, code reviews, and introducing processes that raise the bar for the whole team — while continuously learning from and mentoring each other.
- Participate actively in sprint ceremonies — planning, retrospectives, and iterative delivery — and contribute to continuous team process improvements.
- Monitor production systems and respond quickly to incidents to ensure stable, reliable operation of our services.
Requirements
- 3+ years of professional experience in backend or fullstack web application development with a modern programming language.
- Professional development experience in TypeScript or Scala.
- In-depth knowledge and experience with relational database design and SQL.
- Understanding and experience writing and maintaining automated test suites (Integration tests, Unit tests, Property based tests…)
- Knowledge of functional programming concepts and paradigms.
- Knowledge of software architecture and design principles — you are comfortable making architectural decisions independently and can justify tradeoffs clearly to teammates.
- Experience making pragmatic tradeoffs between delivery speed, code quality, and technical debt — and communicating those decisions to stakeholders.
- Demonstrated ability to pick up an unfamiliar language or framework in a professional setting.
- Hands-on experience working in an agile team, including sprint planning, retrospectives, and iterative delivery.
- Business level language skills in English.
Nice to haves
While not specifically required, tell us if you have any of the following.
- Experience re-architecting or redesigning a legacy codebase.
- Experience with AWS or other cloud platforms.
- Experience with React/TypeScript on the frontend — we value engineers who can contribute across the stack.
- Fluency with AI coding tools such as Cursor, Claude Code, or similar.
- Japanese language ability (spoken and/or written).
- Experience working in remote teams, especially with asynchronous working styles.
Compensation
¥6,000,000 ~ ¥9,000,000 annually.
