Job Description
Career Opportunity for a Java Software Engineer in Japan!
■ Java Software Engineer
■ Company Overview
An e-commerce, fintech, digital content and communications company with more than 30,000 employees, and operations in 30 countries and regions.
■ Your Role and Responsibilities
This Department builds and operates the mission-critical systems that power these logistics services. Every package delivered to a customer depends on the reliability and performance of the platforms we develop. As a software engineer on our team, you’ll solve challenging distributed systems problems while building highly available backend services that support millions of customers and merchants across e-commerce platform.
●Build mission-critical systems that directly support one of Japan’s largest e-commerce platforms.
●Design and develop highly scalable backend services.
●Solve challenging distributed systems and performance problems.
●Work with modern cloud-native technologies.
●Influence technical design and architecture.
●Collaborate with experienced engineers across multiple platform teams.
●Take ownership of services from design through production operations.
<Responsibilities>
●Design, develop, and maintain scalable backend services using Java.
●Design reliable and highly available distributed systems.
●Improve system performance, scalability, and operational efficiency.
●Collaborate with platform and framework teams to improve developer productivity.
●Participate in architecture discussions and technical design reviews.
●Monitor production systems and contribute to incident response and continuous improvement.
●Write clean, maintainable, well-tested production code.
●Contribute to engineering best practices.
■ Experience and Qualifications
● More than 6 years of professional Java development experience.
●Deep expertise in Java, Micronaut, and modern backend development.
●Proven track record designing and delivering production-grade RESTful APIs and/or gRPC services
●Proven experience designing, building, and operating microservice architectures at scale.
●Proven production experience designing event-driven systems with Kafka, including partitioning strategies, consumer group management, and failure handling.
●Deep experience building and operating scalable, highly available distributed systems.
●Hands-on production experience with reactive programming (Reactor, RxJava, etc.)
●Experience diagnosing and resolving distributed systems failures in production.
●Production experience deploying, scaling, and operating services on Kubernetes.
●Experience developing cloud-native applications on Kubernetes and private cloud platforms; AWS exposure is a plus.
●Experience with CI/CD pipelines and Git.
●Experience with capacity planning and performance tuning at scale.
●Strong understanding of software architecture principles and design patterns.
●Experience leading technical design reviews and making architectural decisions.
●Deep experience with relational and NoSQL databases (MySQL, Oracle, or Couchbase), including query optimization, schema design, and performance tuning.
<Development Environment>
●Java
●Kotlin (Gradle scripts and tooling)
●Micronaut
●Kubernetes
●Docker
●Kafka
●gRPC / Protocol Buffers
●REST APIs
●MySQL / Oracle / Couchbase
●Redis
●Gradle
●Git
●CI/CD (Jenkins)
●Elastic / Kibana
■ Additional Preferred Qualifications
● Experience working in Agile/Scrum teams.
●Experience with monitoring and observability tools such as Elastic/Kibana, Prometheus, or Grafana.
●Experience working on large-scale, high-traffic, mission-critical backend systems.
●Experience working in a globally distributed engineering team.
●Comfort working with AI-powered developer tools (coding assistants, internal chatbots, etc.).
●Excellent problem-solving and communication skills.
■ Good Reasons to Join
● Hybrid position in Japan
● Work with International team members
■ Work Location
Tokyo, Japan
Details will be provided during the meeting.