Job Description
Career Opportunity for a Java Software Engineer in Japan!
■ Java Software Engineer (English speaking position)
■ 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
Our systems power warehouse operations across Japan, enabling inventory management, receiving, shipping, fulfillment, delivery scheduling, shipment tracking, and customer notifications. We also support Super Logistics, providing logistics services for merchants and helping them deliver products efficiently to customers. As a software engineer, you’ll solve challenging distributed systems problems while building highly available backend services that support millions of customers and merchants across e-commerce platform.
Position Detail
●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.
■ 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.
<Distributed Systems>
●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.)
<Infrastructure>
●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.
<Architecture & Design>
●Strong understanding of software architecture principles and design patterns.
●Experience leading technical design reviews and making architectural decisions.
<Data>
●Deep experience with relational and NoSQL databases (MySQL, Oracle, or Couchbase), including query optimization, schema design, and performance tuning.
●Experience with Redis for caching and session management.
<Development Environment>
●Java
●Kotlin
●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.)
■ Good Reasons to Join
● Hybrid position in Japan
● Work with International team members
●Language: No Japanese proficiency is required
■ Work Location
Tokyo, Japan
Details will be provided during the meeting.