Data Scientist - AI Lab (AILAB)

Job Description:

Business Overview
Rakuten is one of the biggest marketplace of Japan and is the largest internet ecosystem with a wide range of services ranging from e-Commerce, Travel, Banking, Fintech, Food Delivery, Golf, Insurance, Instant Messaging, Mobile Network etc. Rakuten has over 140 services globally. Our mission is to empower people and society through the internet while aiming at becoming the Global Innovation Company.

Department Overview

The "AI Lab" organization within Rakuten is focused on advancing artificial intelligence applications across the company. It plays a key role in developing innovative AI solutions, and fostering collaboration to integrate AI into various Rakuten services.

The AI Application Engineering Group within the focuses on developing and implementing AI-driven applications to support various business needs. This group works on creating scalable, efficient, and innovative solutions by leveraging AI technologies to enhance Rakuten's services and operations.

Position:
Why We Hire
We’re seeking a data scientist to join the AI Lab team and play a key role in building and improving our AI companion. You’ll operate at the intersection of data science, product insight, and applied research: analyzing early user signals, uncovering system limitations, and driving improvements that shape assistant quality and user value. You’ll also help inform the product roadmap through insights derived from user behavior and the broader Rakuten ecosystem.

Position Details

Responsibilities
- Analyze assistant interactions and internal evaluations to identify improvement opportunities.
- Generate data-driven insights to guide product development and feature prioritization.
- Conduct research to improve agent architecture and user intent understanding to enhance response quality.
- Design and execute experiments, identifying the right metrics to evaluate impact.

- Collaborate with engineers and other Agent Science team members to implement and productionize improvements.
- Leverage diverse datasets across Rakuten’s ecosystem to improve assistant capabilities and deliver customer value.
- Clearly communicate findings and contribute to research and product decisions.
 

Mandatory Qualifications:

- Over 3 years of experience in data science, machine learning, or a related quantitative field.

- Strong Python and ML skills for data processing, analysis, and prototyping.

- Proficiency in SQL and working with large-scale structured data.

- Solid foundation in statistics, experimental design, and predictive modeling.

- Possesses strong problem identification and formulation skills, with a track record of proactively identifying potential issues and developing effective solutions.

- Demonstrated ability to thoroughly research and evaluate potential solutions and identify the optimal approach for a given problem.

- Excellent written and verbal communication skills, with the ability to clearly articulate complex technical concepts to both technical and non-technical audiences.

Desired Qualifications:

- Experience with conversational AI, NLP, or Agentic applications.

- Familiarity with LLM evaluation methods and user interaction data.

- Experience working in product-oriented, cross-functional environments.
- Basic Japanese language skills.

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