Senior Data Scientist, AI Agent Development

Location: Tokyo, Japan (Hybrid / On-site)

Industry: E-Commerce / Tech / Global Digital Ecosystem

Language Proficiency: Business-level fluency in both English and Japanese

About the Role

We are a leading global e-commerce and digital services company dedicated to empowering businesses and society through technology.

Our business support group builds next-generation AI platforms that power operations across our entire ecosystem. The AI Agent Development team focuses on building cutting-edge, AI-native solutions designed to unify communication platforms, drive revenue growth, and optimize operational efficiency for hundreds of thousands of merchant partners.

We are seeking a Senior Data Scientist to lead the development of intelligent AI agents, advanced LLM applications, and data-driven systems that power our next-generation merchant interface.

Key Responsibilities

• AI Agent & LLM Development: Design, build, and deploy advanced machine learning models, fine-tuned LLMs, and agentic workflows to automate and optimize partner/merchant communication.
• RAG Architecture: Build and refine Retrieval-Augmented Generation (RAG) systems to deliver highly accurate, context-aware responses to complex inquiries.
• Data-Driven Insights: Analyze large-scale transactional and behavioral datasets to uncover actionable insights that drive revenue and operational efficiency.
• Cross-Functional Collaboration: Partner closely with Product Managers, Software Engineers, and Business Leads to integrate scalable AI capabilities into production applications.
• Technical Leadership: Mentor junior data scientists and establish engineering best practices for model evaluation, deployment, and AI development lifecycle.

Minimum Qualifications

• Education: Master’s or Ph.D. in Computer Science, Statistics, Mathematics, or a related quantitative field.
• Experience: 5+ years of hands-on experience in Data Science, Machine Learning, or AI Research.
• Technical Stack: Deep proficiency in Python and deep learning frameworks (e.g., PyTorch, TensorFlow).
• LLM & AI Expertise: Strong hands-on experience with Large Language Models (LLMs), prompt engineering, and model fine-tuning techniques.
• Language Proficiency: Business-level fluency in both English and Japanese (TOEIC 800+ equivalent for English) to bridge technical, business, and stakeholder requirements.

Preferred Qualifications

• Track record of building end-to-end AI agent systems or multi-modal conversational AI platforms.
• Technical leadership or project management experience, with a passion for mentoring junior engineers.
• Familiarity with cloud platforms (AWS, GCP) and production MLOps practices.
• Domain experience in E-Commerce, B2B SaaS platforms, or high-scale transactional systems.
• Contributions to open-source AI projects or publications in top-tier machine learning conferences (e.g., NeurIPS, ICML).