【800～1200万円】Java Software Engineer Shipping Calculation Platfo…

【求人No NJB2371890】
■Business Overview
When people think of Rakuten they often think of services such as Rakuten Ichiba Rakuten Books and Rakuten Fashion. Behind the order is a sophisticated logistics platform that manages inventory fulfillment shipping delivery tracking and customer notifications.

The EC Logistics Development 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.

■Department Overview
The EC Logistics Development Department develops and operates the systems that support Rakuten’s logistics ecosystem.

Our systems power warehouse operations across Japan enabling inventory management receiving shipping fulfillment delivery scheduling shipment tracking and customer notifications. We also support Rakuten Super Logistics （RSL） providing logistics services for Rakuten merchants and helping them deliver products efficiently to customers.

Our platforms are business critical. If our systems become unavailable warehouse operations stop and customer deliveries are impacted. As a result reliability scalability and operational excellence are at the core of everything we build.

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 Rakuten’s e commerce platform.

Our mission is to transform logistics through technology by delivering fast reliable and seamless shopping experiences.

We strive to:
・Deliver the right product to the right customer at the right place and time.
・Build reliable logistics platforms that provide exceptional customer experiences.
・Enable merchants to grow their businesses through efficient logistics services.
・Continuously innovate and expand Rakuten’s logistics platform.

We are looking for a passionate Java Software Engineer to build high performance scalable backend systems powering Rakuten’s logistics platform.

You’ll work on large scale distributed systems responsible for critical business operations while collaborating closely with platform engineers architects product managers and operations teams.

This role offers opportunities to solve complex engineering challenges involving scalability reliability performance optimization cloud infrastructure and system architecture.

■Position Details
You’ll have the opportunity to:
・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.
・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.

■Core Technologies
Languages: Java Kotlin
Frameworks: Micronaut Reactive Programming （Reactor/RxJava）
Architecture: Microservices Event Driven Architecture Distributed Systems
Messaging: Kafka gRPC Protocol Buffers
Cloud Infrastructure: Kubernetes Docker AWS Private Cloud
Databases: MySQL Oracle Couchbase Redis
DevOps: Gradle Git Jenkins CI/CD
Observability: Elastic Stack Kibana
APIs: RESTful APIs gRPC Services

■Mandatory Qualifications
6+ years of professional experience in Java backend development
Extensive experience designing building and operating large scale microservices using Java and Micronaut
Proven track record delivering production grade RESTful APIs and gRPC services
Strong expertise in event driven architectures leveraging Kafka
Hands on experience developing and operating highly scalable highly available distributed systems
Solid experience with Kubernetes and Docker in cloud native environments
Skilled in production troubleshooting performance optimization and capacity planning
Strong background in software architecture technical design reviews and architectural decision making
Deep expertise in relational and NoSQL databases including performance tuning and schema design
Experienced with CI/CD automation observability logging and monitoring practices

■Desired 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.