Backend Engineer, Ruby
KomojuMusashino, Japan
Posted January 26, 2026
Full Time
About the Company
KOMOJU is the leading cross-border payment gateway for Japan, powering payments for companies like Steam and TikTok.
Job Description
KOMOJU is looking for a backend engineer to build its payment gateway platform. The ideal candidate has experience working with large web applications, building reliable and performant systems, and testing. The role involves working on large technical projects, ensuring high-quality software, and collaborating with a flat and inclusive engineering team.
Requirements
- Strong experience building backend systems using Ruby on Rails in production environments
- Experience building scalable and performant web applications
- Solid understanding of relational databases and SQL
- Ability to design data models and system architectures
- Strong technical communication skills
- Experience and understanding of common web vulnerabilities and how to mitigate them
- Understanding of software architecture, design patterns, and best practices
Benefits
- Remote work
- Office space for in-person collaboration
- 10 days regular vacation
- Additional 5 days summer vacation
- Additional 5 days winter vacation
- Paid birthday holiday
- Budget for self-learning allowance
- Access to the O'Reilly Learning Platform
- Language training for Japanese/English
- Twice a week office lunch
