Senior Data Scientist / シニアデータサイエンティスト - Mercari Marketplace

The mission of the Data Science Team is to maximize user engagement and long-term value (LTV). We design and develop sophisticated models and systems for Personalized CRM, with the ultimate goal of elevating the overall Mercari user experience.

We achieve this through two strategic pillars: driving independent, high-impact initiatives owned directly by our team, and collaborating horizontally with product and engineering teams across the entire organization to integrate data-driven intelligence into every corner of the marketplace.

As a Senior Data Scientist, you will lead complex product and technical initiatives, collaborating closely with backend teams, infrastructure specialists, designers, marketers, and product managers. You will drive architecture design, ensure technical excellence across platforms, and influence cross-team decisions to shape Mercari’s next generation of AI-driven product experiences., * Identify high-impact opportunities to architect data-driven, personalized CRM strategies; advocate for innovative solutions and build cross-functional momentum to turn vision into reality.

• Design, develop, and deploy sophisticated statistical models, machine learning models, robust evaluation frameworks, and automated inference pipelines (Batch/Stream) with comprehensive monitoring.
• Execute end-to-end data exploration and modeling to resolve complex business bottlenecks and optimize platform performance.
• Translate complex technical findings into actionable insights, collaborating closely with stakeholders to refine models through every stage of the development lifecycle.
• Partner with leadership to shape strategic proposals that maximize Mercari’s data science and engineering capabilities.
• Advocating application of best practices in analysis, modelling, and code hygiene.

Unique Challenges

• End-to-End Project Ownership: The opportunity to lead the entire project lifecycle-from initial conceptualization and stakeholder buy-in to technical execution and post-launch optimization.
• Defining the Frontier: You will be responsible for architecting cutting-edge CRM and personalization solutions that don’t yet have a blueprint. This requires a rare blend of deep technical mastery and domain intuition to navigate uncharted territory and establish new industry standards for marketplace data science., * Skill assessment: For engineering positions, you will be asked to complete a skill assessment on HackerRank or GitHub. For non-engineering positions, you may be asked to complete an assessment depending on the position. (The timing of the assessment may coincide with the interview process.)
• Interview: The number of interviews may vary depending on the position.
• Reference check: We will ask for online references around the timing of the final interview.
• Offer: Offers will be determined carefully in consideration of the final interview and the reference check.

• PhD or MSc in Statistics, Mathematics, Computer Science, or a related quantitative field.
• 5+ years of experience leveraging advanced analytics / systems to drive strategic business decisions.
• Strong command of statistical analysis, machine learning algorithms, A/B testing, and causal inference.
• Demonstrated ability to work with Marketing, Product, and Engineering teams to rapidly iterate on products and execute high-impact features.
• Exceptional verbal and written communication skills with the ability to influence executive-level decision-making.
• Proficiency in Python and SQL.

Preferred Experience/Skills

• Strong Ownership & P/L Mindset: Proven track record of taking full accountability for achieving business KPIs. You possess a “results-first” mentality, ensuring that data science initiatives translate directly into measurable top-line growth.
• Relentless Execution: Ability to drive projects to completion despite technical hurdles or shifting priorities, maintaining a high bar for speed and quality in a fast-paced environment.
• Domain Expertise: Prior experience in Marketing Science or CRM optimization within a high-growth tech environment.
• MLOps Capability: Experience as an ML Engineer developing and maintaining production-grade inference pipelines (both batch and real-time streaming).
• Leadership: Proven experience leading large-scale projects “end-to-end”-from the initial proposal and resource planning to final delivery and maintenance.

Mercari Engineering Principles are a shared understanding that serves as the foundation of engineering beliefs and behavior at Mercari. The Engineering Principles are designed to complement the organizational identity (Mercari’s mission, values, and culture) from an engineering viewpoint.

These principles ultimately help us achieve Mercari’s mission by defining the ideal state we seek to realize in the long term.

• Passion For The Product
• Grow Together
• Solve Through Mechanisms
• Collaborate Openly, Circulate all forms of value to unleash the potential in all people

“What can I do to help society thrive with the finite resources we have?” The Mercari marketplace app was born in 2013 out of this thought by our founder Shintaro Yamada as he traveled the world. We believe that by circulating all forms of value, not just physical things and money, we can create opportunities for anyone to realize their dreams and contribute to society and the people around them. Mercari aims to use technology to connect people all over the world and create a world where anyone can unleash their potential. For more information about Mercari Group’s mission, see Mercari’s Culture Doc

Recruiting at Mercari

At Mercari Group, we value empathizing with and embodying the mission and values of the Group and each company. To promote the creation of an organization that maximizes the total amount of value exhibited by all members, we would like to understand the experience and skills of each candidate as accurately as possible.