Senior Staff Machine Learning Engineer (Coupang AI Foundations)

Coupang

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++  Company Introduction   We exist to wow our customers. We know we’re doing the right thing when we hear our customers say, “How did we ever live without Coupang?” Born out of an obsession to make shopping, eating, and living easier than ever, we’re collectively disrupting the multi-billion-dollar e-commerce industry from the ground up. We are one of the fastest-growing e-commerce companies that established an unparalleled reputation for being a dominant and reliable force in South Korean commerce.   We are proud to have the best of both worlds — a startup culture with the resources of a large global public company. This fuels us to continue our growth and launch new services at the speed we have been since our inception. We are all entrepreneurs surrounded by opportunities to drive new initiatives and innovations. At our core, we are bold and ambitious people that like to get our hands dirty and make a hands-on impact. At Coupang, you will see yourself, your colleagues, your team, and the company grow every day.   Our mission to build the future of commerce is real. We push the boundaries of what’s possible to solve problems and break traditional tradeoffs. Join Coupang now to create an epic experience in this always-on, high-tech, and hyper-connected world.  Job Overview:  As a Senior Staff Backend Engineer - Cloud Infrastructure, this role will focus on Cloud Platform Infrastructure, Services and processes at its best to enhance Cloud infrastructure reliability & system efficiencies, productivity, availability, scalability and system quality at 10X scale. This role will be responsible for diving deep into business problems, understanding current customer pain points, system domain, current Platform limitations (if exists) and then work closely with engineering teams / leaders to design and architect new system / services leveraging cloud infrastructure that can scale 10X better in terms of reliability, availability performance and efficiency. This includes providing system architecture artifacts, accountability on cloud infrastructure choices that can perform and scale at 10X level but are still efficient, guidance on using right machine type, network designs, deployment automation etc . You will be part of a Global team working from different locations but still works as a central connected unit.  Key Skills and Role Responsibilities:  * Strong experience on Cloud DevOps tools and coding (CI/CD, IaC, Terraform, Python, Cloud Formation, Ansible, GitHub, CircleCI, Jenkins and Infra Automation) * Self-service code development and end-to-end back cloud deployment automation for application stack. * Provide a roadmap and vision for scalable and robust growth for your cloud infrastructure and platform services to enable achieving 99.999% availability. * Strong technical analytical & design capability to understand common & shared platforms, web, & services API with underlying data to provide appropriate network, infrastructure recommendations * Strong working experience on Kubernetes, Docker, Linux and cloud services integrations. * 100% accountable for the reliable, scalable and optimized cloud architecture, design and platform services. * Serve as Cloud Engineering for Cloud infrastructure Architecture, Design and Deployment and maintenance for highly reliable and scalable applications. * Solves complex technical problems in Public Clouds (AWS, Azure, GCP) and Private Cloud environment and improves Operational Excellence. * Strong ability to dive deep to understand current cloud infra and systems architecture to provide strategic partnership and improvements on network usage, role management, CDN, domains and cloud infra security. * Analyze complex distributed production deployments and recommend ways to optimize performance and/or automate processes by managing continuous integration servers, utilizing monitoring and testing tools. * Identify opportunities to make disruptive improvements in cloud infrastructure usage, operations and services with high degree of systematic automation. * Possess expert knowledge in performance (sub millisecond latencies), scalability, availability (99.999% uptime), enterprise architecture best practices * Exert technical influence over multiple teams, increasing their productivity and effectiveness by sharing your deep knowledge and experience. * Strong problem-solving skills, analytical capabilities, and attention to details * Provide a roadmap and vision for scalable and robust growth for cloud infrastructure and platform services * Collaborate with customers, stakeholders and lead engineers on key mission-critical projects Preferred Qualifications:  * Bachelor's degree and/or Master's degree in Computer Science or equivalent with 15+ Years of strong hands-on experience in cloud platform engineering. * 10+ years of hands-on experience on system engineering, Cloud DevOps and Cloud SRE * 7+ years of hands-on experience leading system design, architecture leveraging AWS or Azure services * 10+ years of demonstrable hands-on experience building and operating infrastructure as code (IaC). Comfortable with many flavors of Linux * 10+ year’s of hands-on experience in building high-performance, highly-available and scalable distributed systems in the cloud. * 7+ year’s of hands-on experience in building and managing high-performance, highly-available and scalable Hybrid Cloud cloud environments . * Excellent cross-group collaboration, outstanding verbal and written communication. * AWS Certification Advance Architecting, Developing on AWS, * Strong hands-on experience on automating App stack deployments through IaC using Terraform, Python or Go. * 10+ years of hands-on experience as a Cloud Infra Engineering * Team leading experience * Excellent cross-group collaboration and communication skills    Basic Qualifications:  * Bachelor’s degree and 7+ years of total experience    * Ability to solve problems through creative thinking and partnerships with other teams    * Ability to attain challenging targets through goal-setting and personal drive     Pay & Benefits  Our compensation reflects the cost of living across several US geographic markets. At Coupang, your base pay is one part of your total compensation. The base pay for this position ranges from $174,000/year to $299,000/year. Pay is based on several factors including market location and may vary depending on job-related knowledge, skills, and experience. Annual bonus is 0-20% of the base salary. General Description of All Benefits  * Medical/Dental/Vision/Life, AD&D insurance      * Flexible Spending Accounts (FSA) & Health Savings Account (HSA)     * Long-term/Short-term Disability     * Employee Assistance Program (EAP) program    *  401K Plan with Company Match     * 18-21 days of the Paid Time Off (PTO) a year based on the tenure     * 12 Paid Holidays     * up to 6 weeks of Paid Parental leave     * Pre-tax commuter benefits     * MTV - [Free] Electric Car Charging Station    General Description of Other Compensation       “Other Compensation” includes, but is not limited to, bonuses, equity, or other forms of compensation that would be offered to the hired applicant in addition to their established salary range or wage scale.     Privacy Notice   * Your personal information will be collected and managed by Coupang as stated in the Application Privacy Notice located below: https://www.coupang.jobs/privacy-policy/   Coupang is an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, or gender (including pregnancy, gender identity, gender expression, sexual orientation, transgender status), national origin, age, disability, medical condition, HIV/AIDS or Hepatitis C status, marital status, military or veteran status, use of a trained dog guide or service animal, political activities, or affiliations, citizenship, or any other characteristic or class protected by the laws or regulations in the locations where we operate. If you need assistance and/or reasonable accommodation in the recruiting process due to a disability, please contact us at usrecruiting@coupang.com.    Job Requisition ID: 8784

Coupang

Company Introduction  We exist to wow our customers. We know we’re doing the right thing when we hear our customers say, “How did I ever live without Coupang?” Born out of an obsession to make shopping, eating, and living easier than ever, we are collectively disrupting the multi-billion-dollar commerce industry from the ground up and establishing an unparalleled reputation for being leading and reliable force in South Korean commerce.   We are proud to have the best of both worlds — a startup culture with the resources of a large global public company. This fuels us to continue our growth and launch new services at the speed we have been since our inception. We are all entrepreneurs surrounded by opportunities to drive new initiatives and innovations. At our core, we are bold and ambitious people that like to get our hands dirty and make a hands-on impact. At Coupang, you will see yourself, your colleagues, your team, and the company grow every day.     Our mission to build the future of commerce is real. We push the boundaries of what’s possible to solve problems and break traditional tradeoffs. Join Coupang now to create an epic experience in this always-on, high-tech, and hyper-connected world.    Role Overview  At Coupang, we invest in providing the best product experience for our customers. The AI and Knowledge Engineering team’s mission is to provide the best possible technical solution to achieve the optimal experience for our customers. We innovate and advance the space of Knowledge Graphs, AI agents, LLMs, AIGC, ML, NLP, CV and multi-modal models. We are looking for engineers who want to work on cutting edge technology, that is the intersection of Semantic knowledge bases, AI agents, NLP, LLM, AIGC, ML and software engineering. Come join us to help create a world class team advancing the AI/NLP/AIGC/ML/LLM/RL/Knowledge Graph technologies.   What You Will Do  * Work on GenAI, AI agents' systems to solve complex eCommerce scenarios. * Develop large language and vision understanding/generation models for predictive and compound AI Models * Train foundational models that can help with building learning systems. * Define process and experiments for an E2E foundation model. * Build E2E AI pipelines for storing/servicing foundational models. * Mentor and guide team members on frameworks, methodologies related to data lakes, data normalization, dimension reduction, visualization, statistical models. * Ensure Model training is security, compliance aware. * Collaborate with cross-team members to understand the requirements ensuring the foundational models; knowledge captured aligns with the company’s overall AI strategy.    Basic Qualifications * 5+ years of demonstrated data science, experience in building large scale foundational models for eCommerce scenarios. * Expertise in large language model post-training and deployment. * Deep understanding of AI/LLM/AIGC/ML architecture. * Strong statistical/mathematical background in defining metrics, learning functions, and result analysis. * Significant experience in SQL, Python, PySpark, Scala and R * Proficiency in PyTorch/TensorFlow, Spark, BigQuery * Proficiency in AI coding Cursor/Windsurf/Claude Code/Codex. * Experience creating complex data visualization tools, frameworks, and techniques. * Experience in dimension reduction in big data. * Proficient in cloud analytical stacks [ Lakes, warehouse, ETL pipelines] * Experience with inference platforms in AWS, Azure, and other open-source platforms. * Result-oriented, with a bias towards customer obsession, flexibility, and impact. * Strong written and verbal communication and teamwork skills * Passion for Large language models, NLP, and Machine Learning at scale * Education: B.S, M.S in Computer science or Mathematics, or related field   Recruitment Process  * Application Review -> Phone Interview -> Onsite (or Virtual Onsite) Interview –> Offer  * The exact nature of the recruitment process may vary according to the specific job and may be changed due to scheduling or other circumstances.  * Interview schedules and the results will be informed to the applicant via the e-mail address submitted at the application stage.     Details to Consider   * This job posting may be closed prior to the stated end date for application if all openings are filled.  * Coupang has the right to rescind an offer of employment if a candidate is found to have submitted false information as part of the application process.  * Those eligible for employment protection (recipients of veteran’s benefits, the disabled, etc.) may receive preferential treatment for employment in accordance with applicable laws.  * Job titles and responsibilities may be subject to change depending on the candidate’s overall experience, etc. This will be communicated to the candidate at the appropriate time before the offer.  * Hiring may be restricted in case the legal qualifications required for hiring and work performance is not met.    Privacy Notice   Your personal information will be collected and managed by Coupang as stated in the Application Privacy Notice located below.   https://privacy.coupang.com/en/land/jobs/

Coupang

쿠팡은 고객 감동 실현을 위해 존재합니다. 고객들이 "쿠팡 없이 그동안 어떻게 살았을까?" 라고 말할 때, 비로소 우리의 미션을 실현하고 있음을 알 수 있습니다. 고객들의 쇼핑과 식사, 생활 전반을 편하게 만들겠다는 유일한 집념으로 쿠팡은 수억 달러 규모의 이커머스 산업 전반의 혁신을 이끌고 있습니다. 쿠팡은 가장 빠르게 성장하는 이커머스 기업 중 하나로, 국내 커머스 업계에서의 독보적인 입지와, 고객 신뢰를 구축했습니다. 쿠팡은 스타트업 문화를 기반으로 한 글로벌 대형 상장사라고 자부합니다. 이것이 창립 당시의 기민함을 유지하며, 신규 서비스를 끊임없이 출시하며 비즈니스를 확장해 나가는 우리의 성장 동력입니다. 쿠팡의 모든 임직원에게는 기업가 정신을 갖추고 새로운 혁신과 이니셔티브를 추진할 수 있는 기회가 주어집니다. 주저 없이 일에 뛰어들어 성과를 이루고자 하는 과감성이, 바로 쿠팡이 일하는 방식의 본질입니다. 쿠팡에서는 여러분 자신, 동료, 팀 그리고 회사 전체가 매일 성장하는 모습을 목격할 것입니다. 쿠팡의 모든 직원은 커머스의 미래를 만들겠다는 쿠팡의 미션에 진심입니다. 우리는 고객의 문제를 해결해 나가고, 전통적인 관념과 통념에 맞서며 실현 가능한 한계를 뛰어넘고 있습니다. 고가용성 (always-on) 과 최첨단의 앞선 기술 (high-tech), 초연결사회 (hyper-connected world) 에서의 놀라운 업무 경험을 원하신다면, 지금 바로 쿠팡에 합류하세요.   조직 소개 (About the Team) Coupang Ads 플랫폼은 매달 수천만 명의 고객과 수십만 명의 판매자/광고주를 정밀하게 연결하는 테크 조직입니다. Ads Growth 팀은 최첨단 머신러닝, 생성형 AI(Generative AI), 그리고 에이전틱 AI(Agentic AI) 기술을 활용하여 쿠팡의 광고 비즈니스 성장을 견인하고 광고주의 투자 수익률(ROI)을 극대화하는 혁신적인 솔루션을 구축합니다. 우리는 대규모 실시간 옥션(Auction) 시스템 최적화, 정밀한 타겟팅, 그리고 광고 캠페인 생성부터 노출/최적화까지의 전 과정을 자율적으로 수행하는 차세대 AI 시스템을 개발하고 있습니다.   역할 개요 (Role Overview) Senior Staff Machine Learning Engineer는 Ads Growth 팀의 핵심 기술 리더(IC)로서, 쿠팡 광고 플랫폼의 차세대 아키텍처를 설계하고 중장기 기술적 방향성을 정의합니다. 단순히 모델을 학습시키는 것을 넘어, Multi-Agent 시스템, 자율적 추론 파이프라인, 보상 기반 강화학습(RL) 등 최신 기술을 대규모 프로덕션 환경에 이식하여 비즈니스 임팩트를 만들어냅니다. 특히 글로벌 협업 환경에서 한국어와 영어 양국어로 명확하게 소통하며 크로스 기능(Cross-functional) 조직을 리드하고, 복잡한 트레이드오프 관계를 조율하는 선구자적인 역할을 수행합니다. 주요 업무 (Responsibilities) * 차세대 에이전틱 시스템 설계: LangGraph, ReAct 등을 활용하여 멀티 에이전트 오케스트레이션, 도구 사용(Tool-usage), 장단기 메모리 및 자율 추론 파이프라인을 갖춘 대규모 Agentic AI 시스템 구축 * 광고 최적화 및 모델링: 포스트 트레이닝 강화학습(RLHF, RLAIF, Reward Modeling)을 도입하여 광고주 성과 및 사용자 경험을 극대화하는 보상 기반 최적화 모델 개발 * LLM 고도화 및 인프라 구축: 대규모 언어 모델(LLM)의 파인튜닝, 지식 증류(Distillation), 대규모 분산 서빙 및 실시간 추론(Inference) 효율화 아키텍처 리드 * 데이터 기반의 혁신: 복잡하고 거대한 광고 데이터셋을 탐색하여 숨겨진 패턴을 식별하고, 이를 계량화된 광고 퍼포먼스(CTR, CVR, tROAS 달성률 등) 개선으로 연결 * 글로벌 기술 리더십 및 얼라인먼트: Ads Growth의 중장기 기술 로드맵을 설정하고, 국/영문 테크니컬 디자인 문서(Design Docs) 작성을 통해 글로벌 유관 부서(Product, Infrastructure 등)와 복잡한 트레이드오프 조율 및 싱크 얼라인 * 엔지니어링 엑설런스: 철저한 코드 리뷰, 테스트 자동화, CI/CD, 시스템 디자인 가이드를 통해 최고 수준의 소프트웨어 엔지니어링 프랙티스 전파 (Claude Code 등 AI 코딩 에이전트를 적극 활용하여 개발 워크플로우 가속화)   자격 요건 (Basic Qualifications) * 컴퓨터공학, 엔지니어링, 수학, 통계학 또는 관련 분야의 학사 학위 이상 * 탁월한 커뮤니케이션 스킬 보유자 (글로벌 팀 및 다국적 이해관계자와의 원활한 업무 조율 체계 필수) * 대규모 프로덕션 머신러닝(ML) 시스템을 설계, 배포 및 운영한 10년 이상의 전문 경력 * Agentic AI 시스템 구축 경험: 멀티 에이전트 오케스트레이션, 플래닝, 자율 추론 파이프라인 설계 및 구현 경험 (예: ReAct 프레임워크, LangGraph 등 활용) * 고도화된 소프트웨어 엔지니어링 역량 및 프로그래밍 스킬 (Python 숙련자, Test-driven 개발, CI/CD 및 확장 가능한 시스템 디자인 역량) * 기술 리더십 역량: 주도적으로 기술 방향성과 로드맵을 설정하고, 엔지니어들을 멘토링하며, 전사적/교차 부서 간 얼라인먼트를 이끌어낸 경험   우대 사항 (Preferred Qualifications) * 컴퓨터공학, 엔지니어링, 수학, 통계학 또는 관련 분야의 석사 또는 박사 학위(Ph.D.) * 대규모 디지털 광고 시스템(Advertising Systems)에 대한 깊은 이해 및 개발 경험 * 보상 기반 최적화(Reward-based optimization)를 위한 포스트 트레이닝 강화학습(RLHF, RLAIF 또는 도메인 특화 리워드 모델링) 경험 * LLM 파인튜닝, 증류(Distillation), 대규모 serving/inference 인프라 최적화 경험 * End-to-End 모델 트레이닝 및 서빙 파이프라인(Feature Store, 온/오프라인 평가, A/B 테스트 프레임워크) 구축 경험 * 복잡한 대용량 데이터셋에서 인사이트를 도출하고, 이를 측정 가능한 광고 성과 지표로 전환한 성공 트랙 레코드 * Claude Code 등 최신 코딩 에이전트/AI 툴을 활용하여 AI 개발 워크플로우를 극대화해 본 경험 * 탁월한 서면 커뮤니케이션 능력 (복잡한 기술적 트레이드오프를 명확한 디자인 문서로 시각화 및 문서화하여 다국적 이해관계자를 설득할 수 있는 역량)   전형 절차 및 안내사항 전형 절차 * 서류전형 > 1차 면접 > 2차 면접 * 모든 면접은 비대면 화상면접으로 진행됩니다. * 전형 절차는 직무별로 다르게 운영될 수 있으며, 일정 및 상황에 따라 변동될 수 있습니다.   참고 사항 * 본 공고는 모집 완료 시 조기 마감될 수 있습니다. * 지원서 내용 중 허위사실이 있는 경우에는 합격이 취소될 수 있습니다. * 취업 보호 대상자(보훈대상자, 장애인 등)는 관련 법률에 따라 채용우대를 받을 수 있습니다. * 직급과 담당 업무 범위는 후보자의 전반적인 경력과 경험 등 제반 사정을 고려하여 변경될 수 있습니다. 이러한 변경이 필요할 경우, 최종 합격 통지 전 적절한 시기에 후보자와 커뮤니케이션 될 예정입니다.   개인정보 처리방침 * 쿠팡 그룹은 입사지원자 개인정보 처리방침(아래 링크)에 따라 귀하의 개인정보를 수집하여 처리합니다. * https://www.coupang.jobs/kr/privacy-policy   서류 반환 정책 * 본 고지는 『채용절차의 공정화에 관한 법률』 제11조 제6항에 따른 것입니다. * 당사 채용에 응시한 구직자 중 최종합격이 되지 못한 구직자는 『채용절차의 공정화에 관한 법률』에 따라 제출한 채용서류의 반환을 청구할 수 있음을 알려 드립니다. 다만, 홈페이지 또는 전자우편으로 제출된 경우나 구직자가 당사의 요구 없이 자발적으로 제출한 경우에는 그러하지 아니하며, 천재지변이나 그 밖에 당사에게 책임 없는 사유로 채용서류가 멸실된 경우에는 반환한 것으로 봅니다. * 위 2항 본문에 따라 채용서류 반환 청구를 하는 구직자는 채용서류 반환청구서[채용절차의 공정화에 관한 법률 시행규칙 별지 제3호 서식]를 작성하여 당사 이메일 (recruitingops@coupang.com) 로 제출하면, 제출이 확인된 날로부터 14일 이내에 지정한 주소지로 등기우편을 통하여 발송해 드립니다. 이 경우 등기우편요금은 수신자 부담으로 하게 되오니 유념하시기 바랍니다. * 당사는 위 2항 본문에 따른 구직자의 반환 청구에 대비하여 채용 여부가 확정된 날로부터 180일 간 구직자가 제출한 채용서류 원본을 보관하게 되며, 그때까지 채용서류의 반환을 청구하지 아니할 경우에는 『개인정보 보호법』에 따라 지체 없이 채용서류 일체를 파기할 예정입니다. * 채용 및 업무 수행과 관련하여 요구되는 법령상 자격이 갖추어지지 않은 경우 채용이 제한될 수 있습니다.   Company Introduction We exist to wow our customers. We know we’re doing the right thing when we hear our customers say, “How did I ever live without Coupang?” Born out of an obsession to make shopping, eating, and living easier than ever, we’re collectively disrupting the multi-billion-dollar e-commerce industry from the ground up. We are one of the fastest-growing e-commerce companies that established an unparalleled reputation for being a dominant and reliable force in South Korean commerce. We are proud to have the best of both worlds — a startup culture with the resources of a large global public company. This fuels us to continue our growth and launch new services at the speed we have been since our inception. We are all entrepreneurs surrounded by opportunities to drive new initiatives and innovations. At our core, we are bold and ambitious people that like to get our hands dirty and make a hands-on impact. At Coupang, you will see yourself, your colleagues, your team, and the company grow every day. Our mission to build the future of commerce is real. We push the boundaries of what’s possible to solve problems and break traditional tradeoffs. Join Coupang now to create an epic experience in this always-on, high-tech, and hyper-connected world.   About the Team The Coupang Ads Platform is a core technology organization that precisely connects tens of millions of customers with hundreds of thousands of merchants and advertisers every month. The Ads Growth team leverages cutting-edge Machine Learning, Generative AI, and Agentic AI technologies to drive Coupang's advertising business growth and maximize advertiser ROI. We are building the next generation of AI systems that autonomously manage the entire advertising lifecycle—from campaign creation and targeting to real-time auction optimization and budget delivery.   Role Overview As a Senior Staff Machine Learning Engineer and a high-level technical Individual Contributor (IC), you will define the technical direction and architect the next-generation foundation for Coupang's advertising platform. Going beyond traditional model training, you will build and scale complex multi-agent systems, autonomous reasoning pipelines, and reward-based reinforcement learning systems in a massive production environment. Operating in a highly global environment, you will bridge technical and cross-functional teams by communicating fluently in both Korean and English, aligning stakeholders across complex engineering tradeoffs.   Responsibilities * Architect Next-Gen Agentic Systems: Design and deploy large-scale Agentic AI systems featuring multi-agent orchestration, tool-usage, planning, memory, and autonomous reasoning pipelines utilizing frameworks such as ReAct and LangGraph. * Optimize Ad Delivery & Modeling: Implement post-training reinforcement learning (RLHF, RLAIF, or domain-specific reward modeling) to build reward-based optimization pipelines that maximize advertiser performance and shopper experience. * Scale LLM Capabilities: Lead the technical implementation of LLM fine-tuning, distillation, and high-throughput, low-latency serving/inference infrastructure at scale. * Drive Data-Driven Innovation: Explore massive, complex advertising datasets to discover non-obvious patterns, translating these insights into measurable advertising performance indicators (e.g., CTR, CVR, and tROAS attainment). * Global Technical Leadership & Alignment: Establish long-term technical roadmaps for Ads Growth. Author comprehensive technical design documents in English and Korean to align cross-functional, multinational stakeholders on complex architectural tradeoffs. * Promote Engineering Excellence: Champion rigorous software engineering practices, including comprehensive testing, automated CI/CD, and robust system design. Proactively accelerate AI development workflows using advanced coding agents (e.g., Claude Code).   Basic Qualifications * Bachelor’s degree in Computer Science, Engineering, Mathematics, Statistics, or a related technical field. * Strong communication skills (Essential for seamless collaboration with global teams and multinational stakeholders). * 10+ years of professional experience in applied machine learning, with a proven track record of shipping and scaling production ML systems. * Experience with Agentic AI Systems: Hands-on experience designing and building multi-agent orchestration, planning, memory, and autonomous reasoning pipelines (e.g., ReAct, LangGraph). * Strong Software Engineering Practices: Proficiency in Python combined with production-grade engineering disciplines (automated testing, rigorous code reviews, CI/CD, and scalable system design). * Proven Technical Leadership: Demonstrated ability to set technical directions, drive long-term roadmaps, mentor engineers, and establish alignment across cross-functional organizations.   Preferred Qualifications * Master’s or Ph.D. in Computer Science, Engineering, Mathematics, or a related technical field. * Deep domain expertise in large-scale Digital Advertising Systems. * Experience with post-training reinforcement learning for reward-based optimization (RLHF, RLAIF, or domain-specific reward modeling). * Experience with LLM fine-tuning, distillation, and efficient serving/inference infrastructure optimization at scale. * Hands-on experience building and managing end-to-end model training and serving pipelines (Feature Stores, online/offline evaluation, and A/B testing frameworks). * A proven track record of diving into massive datasets, uncovering non-obvious patterns, and converting findings into quantifiable advertising performance metrics. * Experience accelerating AI development workflows using advanced coding agents (e.g., Claude Code). * Exceptional written communication skills, with the ability to write clean technical design docs that clearly articulate complex architectural tradeoffs to multinational stakeholders.   Recruitment Process and Others Recruitment Process * Application Review - Phone Interview - Onsite (or Virtual Onsite) Interview – Offer * The exact nature of the recruitment process may vary according to the specific job and may be changed due to scheduling or other circumstances. * Interview schedules and the results will be informed to the applicant via the e-mail address submitted at the application stage. Details to Consider * This job posting may be closed prior to the stated end date for application if all openings are filled. * Coupang has the right to rescind an offer of employment if a candidate is found to have submitted false information as part of the application process. * Coupang does not discriminate against disabled applicants or those with veteran status. We are proud to offer equal opportunities for all applicants. * Job titles and responsibilities may be subject to change depending on the candidate’s overall experience, etc. This will be communicated to the candidate at the appropriate time before the offer. Privacy Notice * Your personal information will be collected and managed by Coupang as stated in the Application Privacy Notice located below. * https://www.coupang.jobs/en/privacy-policy/ Document Return Policy * This notification is given pursuant to Article 11 (6) of the Fair Hiring Procedure Act. * A job applicant, who has applied but not been finally selected for a position at Coupang (the “Company”), may request the Company to return his/her hiring documents submitted pursuant to the Fair Hiring Procedure Act. However, this will not apply where the hiring documents were submitted via the website of the Company or e-mail, or where the job applicant submitted those documents voluntarily without a request from the Company. In addition, if the hiring documents were destroyed due to a natural disaster or any other reasons not attributable to the Company, such documents will be deemed to have been returned to the job applicant. * A job applicant who wishes to request the return of his/her hiring documents pursuant to the main sentence of paragraph 2 above should fill out a “Request for Return of Hiring Documents” [Annex Form No. 3 in the Enforcement Rule of the Fair Hiring Procedure Act] and submit the request to the Company (Coupang Recruiting Team, Tower 730, 570 Songpa-daero, Songpa-gu, Seoul). In such case, within fourteen (14) days from the date of identifying the receipt of the request, the Company will send the hiring documents to the job applicant’s designated address via registered mail. Please be informed that the job applicant is required to pay the postage on the registered mail. * In preparation for a job applicant’s request for the return of hiring documents pursuant to the main sentence of paragraph 2 above, the Company shall retain the original hiring documents submitted by the job applicant for 180 days from the completion of the recruiting process. If no request is made until the end of this period, all of his/her hiring documents will be destroyed immediately in accordance with the Personal Information Protection Act.