Ad Tech Engineer / Machine Learning Engineer - Marketplace

• Employment Status: Full-time
• Work Hours: Full flextime (no core time)
• Office Location: Roppongi

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Role Overview

Unique opportunity in the Ad-Tech field to lead optimization initiatives, leverage data science and machine learning, and make a significant impact at scale.

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Organization / Team Mission

Mercari's Engineering Principles underpin the team's action:

• Passion For The Product
• Grow Together
• Solve Through Mechanisms
• Collaborate Openly

The Ads Optimization Team is responsible for developing and refining algorithms that drive advertising solutions for sellers and advertisers, using technologies like recommendations, search, and machine learning.

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Work Responsibilities

• Lead optimization in Ad-Tech, focusing on campaign goal achievements.
• Use data science and machine learning to address business challenges, build models, and improve productivity iteratively.
• Set mid/long-term business priorities and focus on business impact.
• Employ a data-driven approach to hypothesis generation, evaluation, and model design.

Specific duties include:

• Propose, drive, implement, and validate business improvement initiatives.
• Develop and maintain machine learning models in the advertising field, including recommendation, matching, and classification.
• Apply statistical/data science techniques for product insight and optimization.
• Enhance performance of advanced ML models using image/text embeddings.
• Design time-series models to analyze ad effectiveness and budget optimization.

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Unique Challenges

• Build ad solutions for platforms with >20 million MAUs, influencing the Japanese advertising market.
• Pioneer innovative advertising frameworks leveraging extensive product, fintech, and behavioral data.
• Focus on both business impact and user experience when developing models.
• Own the full ML product lifecycle, from planning through deployment.

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Qualifications

Required:

• Alignment with the organization’s mission and values.
• Proven experience leading optimization in Ad-Tech with tangible business outcomes.
• Basic knowledge of digital marketing.
• Ability to plan, design, analyze data, and deliver actionable outputs.
• Programming skills: SQL, Python, Go.
• Sound understanding of ML and software engineering.
• Experience with ML libraries (e.g., scikit-learn, LightGBM).
• Basic/intermediate statistics and data science knowledge.

Preferred:

• Microservice development using Kubernetes (k8s).
• Building/operating large-scale ETL/ELT pipelines.
• Experience with ad recommender models.
• Experience in large-scale search systems.

Language Requirements: (one of the following)

• Japanese: Native (required) / English: B2 (required)
• English: Native/Fluent (required) / Japanese: nice to have
  More on CEFR

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Learn More

• Careers site
• Mercan
• Social: X / LinkedIn

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Recruiting Process

1. Application screening
2. Skill assessment (HackerRank/GitHub or others, as applicable)
3. Interview (number varies with role)
4. Reference check
5. Offer

Details about our process

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Equal Opportunity Statement

Commitment to Inclusion & Diversity:
No one’s potential should be limited by background. We eliminate discrimination based on age, gender, orientation, race, religion, disability, and beyond. Read our I&D statement.

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