Senior Java Engineer

Job Description Join a team responsible for developing and operating BFF (Backend for Frontend) services and APIs that support one of the largest e-commerce platforms in Japan. This role offers the opportunity to drive technical decisions, solve complex scalability challenges, and lead engineering initiatives across the full software lifecycle. Description * Design, develop, test, and release backend services and RESTful APIs * Build and operate BFF (Backend for Frontend) applications supporting customer-facing experiences * Design scalable solutions aligned with business requirements * Troubleshoot production issues and support critical online systems * Improve system performance, availability, and maintainability * Collaborate with Product Managers, QA Engineers, and cross-functional teams * Lead technical discussions, code reviews, and engineering best practices * Contribute to CI/CD pipelines, observability, and operational excellence * Drive improvements across the development lifecycle, including AI-assisted engineering practices Required Skills & Experience * 5+ years of Java EE development experience * Strong experience designing and developing RESTful APIs * Experience operating and supporting large-scale production systems * Deep understanding of software development lifecycle and engineering best practices * Strong knowledge of code reviews, source control, testing, deployment, and operational processes * Ability to independently design and deliver reliable, maintainable, and high-performance solutions * Proven ability to lead projects and collaborate effectively across technical and non-technical teams * Experience with container technologies such as Docker * Business-level English communication skills Preferred Skills * Experience with Spring Framework * Experience with RDBMS, KVS, or NoSQL technologies * Experience building CI/CD pipelines * Monitoring and observability experience using tools such as Grafana * Experience leveraging AI tools to improve engineering productivity and development workflows Job Offer * Opportunity to work on mission-critical systems at significant scale * Ownership across the full software development life cycle * Exposure to modern cloud-native and distributed architectures * Collaborative environment with experienced engineering professionals * Long-term project stability and career development opportunities * Tokyo-based role * International working environment with English as the primary communication language