Software Engineer, Backend (LLM/GenAI) - Merc

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.

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 .

Position Overview

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.)

As a Backend Engineer on the AI/LLM team at Mercari, you will play a key role in designing, developing, and operating backend systems that support our cutting-edge AI and ML applications. You will work closely with ML researchers, data scientists, and other stakeholders to build robust, scalable, and efficient backend services that drive impactful AI-driven solutions for millions of users.

Specific work responsibilities include the following:

• Design and Develop Solutions: Design, develop, and optimize backend systems and APIs to support the integration and operation of AI/LLM models. Ensure these systems are robust, scalable, and efficient to handle large-scale production environments.
• Collaborate on Product Roadmaps: Work closely with product managers and business development teams to plan and execute the product roadmap for AI-driven features, ensuring alignment with business goals.
• Integrate with External Partners: Collaborate with external partners to understand their system limitations and design solutions that benefit both Mercari and its partners. Ensure smooth integration and operation of AI/LLM solutions with partner systems.
• Enhance Existing Features: Collaborate with internal teams to enhance existing features that depend on other teams across the organization. This may involve refactoring and optimizing existing codebases to improve performance and scalability.
• Develop and Maintain Infrastructure: Build and maintain the backend infrastructure required to support AI/LLM services, including data pipelines, deployment scripts, and monitoring systems.
• Testing and Quality Assurance: Develop and implement comprehensive testing strategies, including unit, functional, and end-to-end testing, to ensure the reliability and performance of backend systems.

Unique and Bold Challenges

• In this position, you will have the opportunity to work on innovative AI-driven products that leverage Mercari Group’s vast data assets, creating high-impact user experiences for tens of millions of users.
• You will face the unique challenge of managing the expectations of stakeholders and partners while ensuring that backend systems are robust and scalable enough to accommodate the expanding feature set and load.
• Work at the intersection of cutting-edge AI research and practical backend development, translating state-of-the-art AI/LLM developments into tangible business solutions.

Required Qualifications

• Shared belief in the mission and values of Mercari Group and its various companies.
• 2+ years of experience working on large-scale backend systems.
• Experience with backend design, development, and operational skills considering the load of large-scale services.
• Ability to design and develop with performance and scalability in mind.
• Good communication and interpersonal skills with the ability to collaborate with multiple stakeholders.
• Knowledge and development experience in software testing, including unit testing, functional testing, and end-to-end testing.
• Knowledge and experience in data model design and queries to efficiently utilize databases (RDBMS, NoSQL).
• Development experience in the cloud, especially with GCP or AWS.
• Development experience in a team using Git/GitHub or similar version control systems.
• Passion for the products and technologies.

Preferred Qualifications

• Experience designing, developing, and operating APIs in Go.
• Proficiency with Python.
• Experience developing and operating with microservices architecture.
• Experience in on-call support of services.
• Experience in integrating development with third parties.
• Experience with AGILE methodology.
• Active participation in the open-source community.

Screening Criterias:

• Familiarity with multiple methods and the ability to select and combine the appropriate ones according to the project.
• The ability to construct hypotheses using marketing theories and structure the customer’s decision-making process.
• For more details, please see this .

Language Requirements

• English: Independent (CEFR - B2) 
• Japanese: Independent (CEFR - B2)
• For more details about CEFR, please see

Working ConditionsEmployment 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 “.” 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
  .

Support

• Relocation support
• Language learning support
• Translation/interpretation support
  .

MediaCorporate Sites

• [Japanese]

Owned Media