Data Scientist, Generative AI & Applied Intelligence - AI & Data Consulting Department (AIDC)

Job Description:

Business Overview

Rakuten Group is a global innovation leader, offering over 140 diverse services to hundreds of millions of customers worldwide.

Department Overview

Our AI & Data Consulting Department (AIDC) drives next-generation AI capabilities across the Rakuten ecosystem. We collaborate with various business units to create high-impact, scalable AI solutions that deliver real business value.

As part of AIDC, we are leveraging our Rakuten Ecosystem unique wealth of data to support Rakuten Mobile, one of the most strategic businesses in Rakuten. We seek a technically solid, product-aware Data Scientist to join us in building intelligent systems to revolutionize operational and marketing capabilities.

Position:

Position Details

As a Data Scientist in AIDC, you will play a critical role in designing and implementing advanced data science and AI-driven solutions for key business domains. You will have strong grounding in machine learning, with good experience in applying generative AI technologies (e.g., LLMs via APIs, agents, retrieval-augmented generation) to solve practical problems. In this role, you’ll work closely with engineers, product managers, and UX teams to ensure that models move beyond proof-of-concept into valuable products.

- Develop and deploy data science solutions from problem scoping through to production and evaluation.

- Apply LLMs and generative AI tools to design task-specific agents, pipelines, and solutions via APIs and frameworks.

- Collaborate on the integration of AI components into Rakuten’s products, working with PDMs, PJMs, designers, and engineers.

- Conduct prompt engineering, evaluation, and optimization for real-world generative AI use cases.

- Utilize structured and unstructured data (including text, image, and behavioral data) from across Rakuten's services to generate business insights and solutions.

- Perform exploratory analyses and feasibility studies in rapidly evolving AI domains.

- Contribute to user-centric solution design via engagement with UX experts and feedback loops.

- Stay current with research trends in LLMs, RAG pipelines, agent frameworks, and AI toolchains (LangChain, LlamaIndex, etc.).

- Proactively identify opportunities where generative AI can add value across Rakuten services.

Work Environment

- A dynamic, forward-thinking team within one of the world’s most data-rich organizations.

- Opportunities to work on impactful AI initiatives at a global scale.

- Access to cutting-edge AI infrastructure and enterprise-grade LLM environments.

- A collaborative, diverse, and inclusive working environment with flexible work options.

- Career growth through exposure to both technical depth and product-oriented breadth.

Mandatory Qualifications:

- 4+ years of relevant experience in data science, applied ML, or AI product development.

- Strong proficiency in Python and experience with ML/data libraries (pandas, scikit-learn, PyTorch/TensorFlow, etc.).

- Experience with programmatic use of LLMs via APIs (e.g., OpenAI, Claude, Gemini, open-source LLMs).

- Solid understanding of core ML algorithms and generative AI fundamentals.

- Experience working with SQL and big data environments (e.g., BigQuery, Snowflake).

- Familiarity with cloud platforms (AWS, GCP) for data pipelines and model deployment.

- Strong communication and visualization skills for both technical and business audiences.

- Ability to work in cross-functional, collaborative teams.

- Business Level English

Desired Qualifications:

- Hands-on experience with generative AI tools/frameworks (e.g., LangChain, LlamaIndex, RAG-based architectures).

- Exposure to agent design and orchestration using LLM-based components.

- Understanding of fine-tuning/customization of LLMs and foundational models.

- Experience integrating ML/AI systems into production environments or digital products.

- Familiarity with front-end/product design feedback cycles.

- Japanese proficiency (N2 level or above).