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.