Senior Staff Ranking Engineer, Personalization (Mountain View)

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.Role OverviewThe Search & Discovery organization is responsible for optimizing customers' navigation experience and driving long-term growth. Every week millions of customers use search in our app or on coupang.com, more than one third of them make purchases. Over half of the Coupang sales are directly attributed to search and recommendation. Many business initiatives and growth strategies are driven or boosted by ranking and recommendation.This role is an opportunity to build scalable offline and online ML platforms to support ranking and recommendation, and business decision making. You will be handling billions of records of user interaction data, and petabytes of raw log files, and transforming them into data objects that can be easily consumed by engineers and scientists. You will also be responsible for serving complex ML models in real time to help millions of Coupang customers search and discover products. If you are passionate about big data engineering and scalable serving systems, you want to make real business impact, and you are a true problem solver, this is the right job for you.What You Will doDesign features and build large-scale machine learning models and systems to improve ad targeting, relevance, ranking, and engagementDesign and implement large-scale ML systems for search ranking, semantic retrieval, query understanding, and personalized product discovery using state-of-the-art techniques such as transformer-based models, contrastive learning, and vector searchDrive innovation in search relevance and user intent modeling using large language models (LLMs), embedding-based retrieval, and multi-modal learningBuild and optimize ML pipelines using tools such as Apache Spark, Airflow, Kubeflow, and MLflow, ensuring reproducibility, scalability, and operational excellenceDefine and track key performance metrics to evaluate model impact and identify high[1]leverage opportunities for improvementCollaborate cross-functionally with product, engineering, and data science teams to align technical solutions with business goals and customer experienceMentor and grow engineering talent, fostering a culture of technical excellence, experimentation and continuous learningBasic QualificationsBachelor's degree in computer science, electrical engineering, mathematics, statistics or closely related fields7+ years of professional experience in applied machine learningExperience in machine learning, deep learning, and statistical modelingProficiency in Python and/or Java, with experience in building production grade ML systemsPreferred QualificationsMaster’s or PhD in relevant technical fieldsExperience with search systems, information retrieval or recommendation enginesExperience with LLMs, embeddings, and vector search technologiesExperience with cloud platforms such as AWS, Google Cloud Platform including services like Vertex AI, BigQuery or SageMakerExperience working in startup or high-growth environmentsProven ability to lead-cross-functional teams and deliver results in a multicultural, global organizationHands-on experience with modern ML frameworks such as TensorFlow, PyTorch, Scikit[1]learn, Keras, XGBoost, LightGMB, and H2o.aiExperience with ML lifecycle tools such as MLflow, Kubeflow, Weights & Biases, or Amazon SageMakerExcellent communication skills with the ability to explain complex technical concepts to both technical and non-technical stakeholdersDemonstrated ability to work independently and manage ambiguity in fast-paced environmentsPay & BenefitsOur 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 Staff position ranges from $152K/year to $277K/year. Pay is based on several factors including market location and may vary depending on job-related knowledge, skills, and experience.General Description of All BenefitsAnnual bonus is 0-20% of the base salaryMedical/Dental/Vision/Life, AD&D insuranceFlexible Spending Accounts (FSA) & Health Savings Account (HSA)Long-term/Short-term DisabilityEmployee Assistance Program (EAP) program401K Plan with Company Match18-21 days of the Paid Time Off (PTO) a year based on the tenure12 Public Holidays6 weeks Paid Parental leavePre-tax commuter benefitsMTV - [Free] Electric Car Charging StationGeneral 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.Recruitment ProcessApplication Review - Phone Interview - Onsite (or Virtual Onsite) Interview – OfferThe 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 ConsiderThis 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.Privacy Notice Your personal information will be collected and managed by Coupang as stated in the Application Privacy Notice located below: you need assistance and/or a reasonable accommodation in the application of recruiting process due to a disability, please contact us at View email address on apply.placed-app.com Requisition: R0074076