Principal Engineer, ML

Principal Engineer, Ads Serving & ML PlatformWe exist to wow our customers. We know we’re doing the right thing when we hear ourcustomers 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 entrepreneurial 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 dayOur 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 RoleCoupang is seeking a Principal Engineer to define and lead the technical vision for our Ads Serving & ML Platform, one of the company's most critical business systems powered by large-scale machine learning and AI. Advertising plays a vital role in Coupang's ecosystem, enabling customers to discover relevant products while helping advertisers grow their businesses. The Ads platform directly influences customer engagement, advertiser success, and long-term revenue growth at massive scale.As a Principal Engineer, you will own the architecture and technical strategy of the end-to-end ads serving ecosystem, spanning retrieval, ranking, auction, targeting, machine learning infrastructure, and online serving systems. You will identify future technology investments, drive innovation across organizational boundaries, and ensure that our platform continues to scale in performance, reliability, intelligence, and efficiency.This is a highly influential individual contributor role requiring exceptional technical depth, strategic thinking, and cross-functional leadership. You will partner with engineering, machine learning, product, and business leaders to solve some of the most challenging problems in large-scale distributed systems and AI-powered advertising.What You Will DoDefine and drive the long-term technical vision, architecture, and strategy for Coupang's Ads Serving & ML Platform.Lead the design and evolution of large-scale ad serving systems, including retrieval, ranking, auction, targeting, pacing, and measurement.Drive platform modernization and adoption of emerging technologies, including large language models, generative AI, real-time inference, and next-generation ML infrastructure.Identify and lead strategic technical investments that improve advertiser outcomes, customer experience, system scalability, and operational efficiency.Partner with engineering, machine learning, product, and business leaders to align technical direction with company priorities and business objectives.Influence architecture and engineering excellence across multiple organizations through technical leadership, design reviews, and mentorship.Establish best practices for platform reliability, performance, scalability, observability, and operational excellence.Drive measurable business impact through innovations that improve engagement, conversion, relevance, advertiser ROI, revenue growth, system efficiency and cost.Serve as a recognized technical leader and domain expert in large-scale advertising systems and machine learning platforms.Required Qualifications12+ years of experience building large-scale software platforms, machine learning systems, or distributed infrastructure.Proven track record of architecting and operating mission-critical, high-throughput online systems at internet scale.Deep expertise in one or more user-facing machine learning domains, including advertising, search, recommendations, or personalization.Strong understanding of modern machine learning systems, including model training, feature engineering, experimentation, online inference, evaluation, and production operations.Experience building and scaling AI/ML serving infrastructure, including optimization of GPU- and CPU-based systems for latency, throughput, and cost efficiency.Strong understanding of large language models (LLMs), foundation models, retrieval-augmented generation (RAG), and production AI serving architectures.Deep knowledge of retrieval and ranking systems, including: Relevance and personalizationCandidate generation and rankingPrecision, recall, latency, and cost trade-offsOnline experimentation and model evaluationDemonstrated ability to drive significant business impact through technical innovation and platform evolution.Exceptional ability to influence technical direction across multiple teams and organizations without direct authority.Strong software engineering skills in Java, C++, or Python.Experience developing distributed systems that process and serve large-scale datasets with high availability and low latency.MS or above in Computer Science, Engineering, or a related technical discipline.Preferred QualificationsExperience building large-scale advertising platforms, ad ranking systems, auction systems, or sponsored search products.Experience in e-commerce, marketplaces, or consumer internet companies operating at significant scale.Expertise in real-time machine learning, recommendation systems, search infrastructure, or large-scale personalization platforms.Proven contributions to architectural transformations or platform modernization initiatives across large organizations.Strong passion for exploring emerging technologies and translating innovation into business value.Experience working in high-growth, fast-scaling technology companies.PhD in Computer Science, Machine Learning, Artificial Intelligence, or related fields.Pay & BenefitsOur compensation reflects the cost of labor 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 $207,900/year in our lowest geographic market to $386,100/year in our highest geographic market. Pay is based on several factors including market location and may vary depending on job-related knowledge, skills, and experience.  General Description of All BenefitsMedical/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 Public Holidays  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. Coupang is an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to actual or perceived race (including traits historically associated with race, including but not limited to hair texture and protective hair styles), color, religion, religious creed (including religious dress and grooming practices), sex or gender (including pregnancy, childbirth, breastfeeding, and medical conditions related to pregnancy, childbirth or breastfeeding), gender identity, gender expression, sexual orientation, ,ancestry, national origin (including language use restrictions), age (40 and over), physical or mental disability, medical condition, genetic information, HIV/AIDS or Hepatitis C status, family status (including but not limited to marital or domestic partnership status), military or veteran status, use of a trained dog guide or service animal, political activities or affiliations, ancestry, citizenship, family and medical leave status, status as a victim of any violent crime, or any other characteristic or class protected by the laws or regulations in the locations where we operate.Coupang is also committed to providing a safe work environment for its employees and its consumersIf you need assistance and/or a reasonable accommodation in the application of recruiting process due to a disability, please contact us View email address on click.appcast.io.