Machine Learning Research Engineer (AI/LLM) - Mercari

This position requires English language ability. JD is available in English only. 　本ポジションは日本語JDの用意がありません。

Introduction

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.

Equal Opportunity Hiring

Here at Mercari, we work to realize a world in which no one’s potential is limited by their background and everyone has the opportunity to freely create value. We also firmly believe that a mindset of Inclusion & Diversity is essential for us to achieve our mission.This, of course, extends to our hiring practices as well. Mercari is committed to eliminating discrimination based on age, gender, sexual orientation, race, religion, physical disability, and other such factors so that anyone who shares our mission and values can join us, regardless of their background.

For more details, please read our I&D Statement.

Team’s Mission / Work Responsibilities

The AI/LLM Team’s mission is focused on two core pillars, "building" and "enabling" – delivering new AI-driven features and user experiences to maximize the impact of Mercari's business, as well as utilizing AI technologies to enhance productivity across the entire Mercari Group. We do this both through independent initiatives owned by our team, as well as by horizontally collaborating with product and engineering teams across the entire organization.

(Learn more about Mercari's mission and values here.)

As the first dedicated Research Engineer on the team you will be responsible for significantly expanding our foundational tech capabilities, staying up to date with the latest developments in machine learning and AI research and helping us translate this into direct business impact.

Specific work responsibilities include the following:

• Cutting-Edge Research: Stay ahead of the latest developments in AI, ML, and deep learning by reading academic papers, attending conferences, and following industry blogs. Apply this knowledge to drive innovation within the team.
• Develop and Implement Models: Design, build, and optimize AI models to solve complex problems or perform specific tasks. This requires understanding current problems the team is working on and being able to identify, design, and/or modify the algorithms and model architectures best suited to the problem.
• Collaborate with Cross-Functional Teams: Work closely with ML engineers, frontend/backend developers, and other stakeholders to integrate AI solutions into existing projects and create new user experiences.
• Prototype and Test: Develop prototype applications to test the effectiveness of new algorithms and models. Iterate based on feedback and performance metrics.
• Evaluation and Metric Design: Contribute to designing and implementing offline and online evaluation methods to help our team continuously monitor and optimize the performance of our models.

Unique and Bold Challenges

• In this position, you will have the opportunity to work at the intersection of cutting edge research and applied product development, translating the latest developments in AI research into innovative user experiences with large-scale business impact.
• You will be able to leverage Mercari Group’s vast amounts of data to create AI-driven solutions used by tens of millions of people.
• As the first Research Engineer on our team, you will be able to have a significant impact on the future growth and direction of our research initiatives

Required Qualifications

• Shared belief in the mission and values of Mercari Group and its various companies
• Bachelor's degree in Computer Science, Engineering, or a related technical field, or equivalent practical experience.
• Proven experience in machine learning, deep learning, and/or natural language processing (NLP)
• Proficiency in Python and experience with ML frameworks such as PyTorch or TensorFlow. Strong understanding of the architectural patterns of large-scale software applications.
• Demonstrated ability to develop machine learning models at scale, from inception to deployment.
• Strong analytical skills and the ability to tackle complex problems through innovative solutions.
• 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

• Master’s or Ph.D. degree in Computer Science, AI, ML, or a related technical field.
• Direct experience in generative AI and large language model (LLM) research.
• Publications in top-tier AI conferences (e.g., NeurIPS, ICML, CVPR, ICLR, ACL).
• Experience in multilingual and multimodal modeling, reinforcement learning, and efficient training and inference techniques.
• Experience in technical leadership and building/managing R&D teams.
• Active participation in the open-source community with contributions to AI/ML projects.

Screening Criteria

(See this page for details.)

Language Requirements

• English: Proficient (CEFR - C1) – required
• Japanese: Independent (CEFR - B2) – nice to have but not required
  *Check here for more information about CEFR.

Working Conditions

Employment Status

Full-time

• Probationary period: First 3 months after joining the company. (During this period your contract conditions will be the same as that of a permanent employee.)

Office

Roppongi

• Smoking is prohibited within our offices
• Mercari has introduced a work style policy called “Your Choice.” Each member is free to choose whether they want to work in the office or work fully remote. *Exceptions made for certain kinds of work.

Work Hours

• Full flextime (no “core time” or “flex time”)
  *Does not apply to all positions

Holidays

• Two days off per week (as well as national holidays, New Year's break, etc.)
• Paid leave, congratulatory and bereavement leave, relax days, sick leave

Salary

• Annual salary paid in 12 monthly installments (including fixed overtime allowance)
• Based on skills, experience, and abilities
• Reviewed twice a year

Benefits

• Complete health and social insurance
• Incentive program
• Support systems, including those that benefit the employee’s family members
  *See this page for details.

Support

• Relocation support
• Language learning support
• Translation/interpretation support
  *See this page for details.

Media

Corporate Sites

• Mercari, Inc.
• Merpay, Inc. [Japanese]
• Souzoh, Inc.
• Mercoin, Inc.
• Mercari US

Owned Media

• Mercari Careers
• Mercari Engineering Portal
• Mercan - Introduces the people that make Mercari
• Mercari US Careers
• Mercari US Blog