AI-Driven Engineer (Front-end & Back-end) - IT Division, Rakuten Securities, Inc.(Secondment)

Job Description:

Business Overview
"Innovating Asset Building" - Creating the future as the financial hub of the Rakuten Ecosystem.
Rakuten Securities is a core internet brokerage firm within the Rakuten Group, which operates over 70 services globally. Our goal goes beyond providing financial products; we aim to merge the Rakuten Ecosystem's vast data with cutting-edge technology to transform "asset building" into a seamless, everyday activity for everyone.
- Fusion of User Base and Technology: By seamlessly connecting the Rakuten Ecosystem's extensive data with financial services, we create unique user experiences unmatched by traditional brokerages. We continue to set new industry standards through asset formation support (NISA, iDeCo), AI-driven investment solutions, and partnerships with IFAs.
- The Frontline of Transformation: We are currently undertaking a massive core system overhaul alongside a radical reconstruction of our "next-generation development process" based on AI. We are in an exciting phase for engineers and PMs, involving legacy modernization and the evolution of AI-driven development styles.
- Responsibility and Authority: We maintain the robustness of critical social infrastructure while realizing high-speed new development. Rakuten Securities offers the unique opportunity to achieve this difficult balance using the group's solid network and the latest technology stack.

Department Overview
Redesigning the development process for financial infrastructure with AI.
Our mission is to evolve the entire development lifecycle of Rakuten Securities services (Web, Apps, and Core Systems) into an "AI-Driven" ecosystem. We aim to go beyond simple efficiency and establish a "new standard of development" where AI guarantees both quality and speed. From front-end to back-end, you will implement AI as a "development partner" rather than just a tool, working closely with our development partners.
- Social Implementation of Large-Scale Financial Infrastructure x AI: Serving 14 million accounts, our services are essential social infrastructure. In this high-robustness environment, you will take on the challenge of implementing the latest LLMs and AI Agents to fundamentally transform our development practices.
- Shift from "Coding" to "AI Conducting": Move from a style based on coding volume to one based on design philosophy and architecture, maximizing AI capabilities. You will build your career while experiencing "next-generation engineering," where you ensure the quality of AI-generated code and build complex systems alongside AI.

Position:
Why We Hire
Join us in creating the "new standard of AI-powered development" from the front lines.
At Rakuten Securities, we are currently experimenting with embedding AI not just as an auxiliary tool, but directly into our development processes. While traditional methods of manual specification writing, coding, and reviewing are reliable for large-scale financial systems, they require further updates to meet the speed and evolution demanded today.
We aim to build an "AI-first development structure." Led by our engineers, we are redesigning workflows - such as consistency checks in requirements, code generation, and automated testing - using GitHub Copilot and various LLMs.
- Field-Led Process Innovation: We are looking for members who can rewrite development rules and workflows at a practical level, focusing on how to maximize development quality and speed through AI integration.
- Bridging Technology and Practice: How do we implement new AI technologies into the robust, high-security environment of a financial system with hundreds of millions of transactions? We seek individuals who can engage with engineers and spread this new development style with conviction.

Position Details
- AI-Driven Modernization of Front-end Development: Accelerate implementation and improve quality in Web services and apps like "iSPEED" by using AI as a partner. You will optimize code generation with development partners, using tools like GitHub Copilot to streamline component design and UI implementation. You will establish a new workflow that not only increases speed but also ensures the quality of AI-generated code, significantly shortening the UI/UX improvement cycle.
- AI Integration in Back-end and Core Systems: Implement AI-assisted design and automated testing to balance efficiency and robustness in back-end and core systems. You will integrate the analysis and documentation of complex legacy code and the consistency checking of specifications via LLMs into daily processes. By collaborating with development partners and leveraging AI-generated test code and analysis results, you will build a system that achieves both stable operation and rapid development.
- Organizational Deployment of "AI-Driven Development": Beyond project management, you will deploy successful practices across the entire organization to update our development culture. Through sharing know-how, effective prompts, and hosting workshops, you will create an environment where engineers can naturally master AI. As a commander, you will transform the productivity of the entire development process from front-end to back-end.

Work Environment
Team Member 10
Note: This development environment is current as of May 2026.

- AI Development Support & Integrated Environment: GitHub Copilot is standardized for all engineers, and the use of AI-native editors like Cursor is encouraged. We have also built a secure, internal LLM environment for daily large-scale code analysis, design support, and documentation generation.
- Cloud, Infrastructure, & Automation: Based on a hybrid cloud environment (AWS/Azure/GCP), we promote IaC via Terraform and Ansible. We have thoroughly automated processes from infrastructure to applications, including AI-driven test automation and quality checks within GitHub Actions CI/CD pipelines.
- Development & Project Management: We actively use Jira, Confluence, Miro, and Slack, incorporating AI for automated summarization and task visualization. We also build workflows with development partners for real-time technical documentation cross-referencing and design consistency checks via LLMs.
- Freedom to Select Technology and Take Challenges: We have a culture where the team leads the verification of new AI tools and libraries to promote "AI-Driven Development." You will have the autonomy to immediately prototype ideas like "Can we make this more efficient using AI?" and deploy them into production.

Mandatory Qualifications:
- 5+ years of practical software engineering experience.
- Experience in design and implementation for Web or mobile app front-ends, or back-ends.
- Proven track record of autonomously optimizing development processes and solving technical challenges, beyond just writing code.
- Practical experience using AI development tools such as GitHub Copilot, Cursor, or ChatGPT for coding, refactoring, and test generation.
- Ability to learn and validate new technologies quickly, with a proactive mindset to apply them to solve on-site business problems.
- Deep understanding of the development lifecycle (SDLC), including CI/CD and automated testing, with a focus on leveraging AI for efficiency and automation.

Desired Qualifications:
- Experience in financial or securities system development (focus on robustness and security).
- Practical experience in "AI-Driven Development" (e.g., test automation, documentation automation, or AI agent workflow construction).
- Experience in project leadership or team management (PM experience is a plus).
- Experience in automating infrastructure and environment construction using container technology (Docker/Kubernetes) and IaC (Terraform/Ansible).

Other Information:
Additional information on Location
Rakuten Crimson House Aoyama
2-6-21, Minami-Aoyama, Minato-ku, Tokyo
Additional information on Secondment
You will be seconded from Rakuten Group, Inc. to Rakuten Securities, Inc.
Additional information on English Qualification
TOEIC Score exceeding 800
※If you do not currently have a TOEIC score, you will be required to obtain one after joining the company.

#engineer #applicationsengineer #AI #frontendengineer #webdeveloper #RakutenSecurities

Languages:

English (Overall - 3 - Advanced), Japanese (Overall - 4 - Fluent)