フルスタックエンジニア

Overview This position is for software engineer located in Japan.
We Sell Cellular (WSC), an ITOCHU Group company operating within the Circular Tech business, is seeking a Software Engineer to build and
operate the systems that power our device lifecycle, logistics, and marketplace platforms.
This role will contribute to the development of backend services, internal tools, and platform systems supporting critical business operations. You will work closely with engineering teams in the United States and collaborate with Belong Inc., a fellow ITOCHU Group company in Japan that operates within the same Circular Tech business and maintains its own engineering organization.
This is an opportunity to work on high-impact, real-world systems while helping establish foundational engineering practices within a growing global
Circular Tech platform.

We Sell Cellular is a leading U.S.

-based distributor and lifecycle operator of pre-owned mobile devices, and part of ITOCHU Groupʼs global Circular Tech initiative.

• Device lifecycle and inventory management
• Warehouse and logistics operations
• Pricing optimization and operational tooling
• Internal business platforms and integrations

You will contribute to building and evolving these systems while collaborating with global engineering teams across the ITOCHU Group, including Belong  Japan.

• Design, develop, and maintain backend services and APIs using languages such as Python, Go, or Type Script
• Build and maintain scalable and reliable systems supporting internal operations and platform functionality
• Contribute to system architecture and technical design

• Design, implement, and maintain infrastructure using Infrastructure as Code Terraform)
• Build and maintain CI/CD pipelines using tools such as Git Hub Actions
• Manage and operate cloud infrastructure on Google Cloud Platform
• Improve deployment processes, system reliability, and operational efficiency
• Implement monitoring, observability, and operational best practices

• Support production systems, including incident response, troubleshooting,
• Improve system reliability, scalability, and performance
• Contribute to operational automation and continuous improvement

• Design and maintain database schemas and queries using PostgreSQL, CloudSQL, or similar technologies
• Contribute to data platform integration, including interaction with Big Query
  and internal data systems
• Support system reliability, performance, and scalability

• Collaborate with product, operations, and engineering teams across the U.S. and Japan
• Contribute to improving engineering standards, processes, and platform capabilities
• Help integrate modern development tools, including AI-assisted development tools where appropriate

本ポジションは WSC の日本居住のソフトウェアエンジニア向けのものです。
We Sell Cellular（WSC）は、伊藤忠グループの Circular Tech 事業の⼀員として、ニューヨークにおいて中古モバイルデバイスのライフサイクル管理‧物流‧マーケットプレイスを⽀えるソフトウェアプラットフォームの開発‧運⽤を⾏っています。
本ポジションでは、これらのプラットフォームを⽀えるバックエンドシステムお…