Machine Learning Engineer

Job Overview

This position requires English language ability. JD is available in English only.

Machine Learning Engineer, AI/LLM - Mercari
Employment Status: Full-time
Work Hours: Full Flextime (no core time)
Office: Roppongi
For more details, see the Overview of Our Positions section on our Careers site.

About Mercari
Circulate all forms of value to unleash the potential in all people

\u201cWhat can I do to help society thrive with the finite resources we have?\u201d 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\u2019s mission, see Mercari\u2019s Culture Doc

Organization/Team Mission
Mercari Engineering Principles
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\u2019s mission, values, and culture) from an engineering viewpoint.

These principles ultimately help us achieve Mercari\u2019s 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
For more details, please see the following link:
Engineering Culture

The AI / LLM Team\u2019s mission is focused on three core pillars, \u201cproduct\u201d, \u201cenablement\u201d and \u201cresearch\u201d, delivering new AI-driven features and user experiences to maximize product-facing impact for Mercari's business. We do this both through independent initiatives owned by our team, as well as by horizontally collaborating with product, engineering, and research teams across the entire organization.

As a machine learning engineer, you will work on ML architecture and feature engineering that touches all parts of the business as well as internal tooling.

Key Responsibilities

• Develop and Optimize ML Models: Design, build, and optimize machine learning models to solve complex problems and perform specific tasks. Focus on optimizing model performance and scalability to handle large-scale production systems.


• Feature Engineering: Conduct in-depth feature engineering to improve the robustness and accuracy of ML models, particularly in the context of natural language processing (NLP), computer vision, and multimodal learning.


• Model Deployment and Integration: Collaborate with cross-functional teams to integrate ML solutions into existing products and services, ensuring seamless deployment and operational efficiency.


• Research and Innovation: Keep up-to-date with the latest research and advancements in AI and machine learning, and related fields such as NLP and computer vision.


• Engineering Infrastructure: Design engineering infrastructure to support machine learning systems at scale.


• Experimentation and Testing: Conduct A/B testing, experiments, and evaluations to assess the performance and impact of ML models, using insights to inform further iterations and improvements.

Unique Challenges

In this position, you will develop AI-driven solutions that leverage Mercari Group\u2019s vast data assets, creating high-impact user experiences for tens of millions of users.

Work at the intersection of cutting-edge research and practical application, translating state-of-the-art AI/LLM developments into tangible business solutions.

Engage with diverse teams to build and refine large-scale ML infrastructure and systems.

Required Qualifications

• Shared belief in the mission and values of Mercari Group and its various companies.


• Bachelor\u2019s degree in Computer Science, Engineering, or a related technical field, or equivalent practical experience.


• Proficiency in Python and experience with ML frameworks such as PyTorch or TensorFlow. Strong understanding of architectural patterns for large-scale software applications.


• Demonstrated experience in the end-to-end ML lifecycle, from development to deployment.


• Strong analytical skills with the ability to solve complex, unstructured problems.


• Excellent written and verbal communication skills, with the ability to explain technical concepts to non-technical stakeholders.


• Passion for the products and technologies.

Preferred Qualifications

• Experience with deploying AI solutions in large-scale production environments.


• Master\u2019s or Ph.D. degree in Computer Science, AI, ML, or a related technical field.


• Background in generative AI, LLM, and natural language processing (NLP).


• Experience in multilingual and multimodal models, and efficient training and inference techniques.


• Participation in the open-source community and contributions to AI/ML projects.

Language Requirements

English: Proficient (CEFR - C1)
Japanese: Independent (CEFR - B2) optional
For details about CEFR, see here.

About Mercari Group

Careers site: https://careers.mercari.com/en/
Mercan: https://mercan.mercari.com/en/
Social media: X / Linkedin

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.

Recruiting cycle at Mercari Group
Application screening
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