Haken Senior Java Backend Engineer Tokyo E-commerce
About the job
Join one of Japan's leading global e-commerce and internet services companies as a Senior Backend Design Lead (Java) supporting mission-critical checkout systems and high-traffic online platforms.
In this role, you will lead backend architecture and API development for large-scale order and cart systems that support millions of users. You will collaborate closely with Product Managers, QA teams, and engineers across global teams while driving operational stability, scalability, and engineering excellence.
This is an ideal opportunity for experienced engineers seeking exposure to large-scale backend systems, Java enterprise development, cloud-native environments, and modern DevOps practices within an international and English-speaking workplace.
Key Responsibilities
- Lead the full software development lifecycle from design and development through testing and release
- Architect and maintain high-performance backend APIs, batch systems, and data processing services
- Manage troubleshooting and technical incident resolution for large-scale production systems
- Establish coding standards, conduct code reviews, and improve software quality processes
- Collaborate with QA teams and Product Managers to deliver scalable engineering solutions
- Optimize backend system performance and maintain system reliability for mission-critical applications
- Support engineering initiatives focused on operational excellence and continuous improvement
- Contribute to modern infrastructure and DevOps initiatives including CI/CD and monitoring
Required Skills and Qualifications
Experience:
- 5+ years of Full-Stack or Backend Engineering experience focused on Java EE development
- Strong experience developing and operating RESTful Web APIs
- Experience supporting large-scale, high-traffic systems and handling production incidents
- Hands-on experience with enterprise backend architecture and scalable system design
- Experience with modern development tools and backend technologies
Soft Skills:
- Strong ownership mindset with the ability to drive projects independently
- Leadership skills with experience mentoring junior engineers and collaborating across teams
- Excellent analytical and problem-solving capabilities
- Strong communication skills within multicultural engineering environments
- High sense of responsibility managing mission-critical systems
Language Requirements:
- Japanese: Basic level
- English: Business level
Preferred Skills & Qualifications
- Experience with Spring Framework
- Knowledge of RDB, KVS, or NoSQL databases
- Familiarity with Docker, CI/CD pipelines, and Grafana
- Interest or experience using AI tools to improve software development workflows
About the Company
Our client is one of Japan's most recognized global internet and e-commerce companies, operating large-scale digital platforms used by millions of customers daily. The company offers a highly international engineering culture where innovation, scalability, and cutting-edge technologies are central to business success.
Why You'll Love Working Here
- Competitive hourly compensation with long-term project stability
- Hybrid work model supporting work-life balance
- International engineering culture with English as a primary collaboration language
- Access to modern technology stacks and large-scale backend systems
- Employee food hall, casual dress environment, and comprehensive insurance coverage
Don't Miss Out - Apply Now!
