Sr.Staff Back-end Engineer (eCommerce Engineering) at Coupang · Seoul

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 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 at 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 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. Team Overview The Platform Services team within E-commerce Engineering builds, operates, and scales the core backend platform powering essential logic of Coupang’s mobile app and web—includes Login, Auth, Home, Search, Category, Product Detail, Cart, Checkout, and Orders. This role leads the technical direction and architecture of the next-generation of Data Access, Authorization & Authentication platform that delivers reliable and secured customer experience across Korea, Taiwan, Japan, and other global markets. Role Overview As a Senior Staff Backend Engineer (IC), you will shape the long-term technical strategy and architecture of the AuthN & AuthZ platform. You will build infrastructure that provides the right level of access control and monitoring and detection and response in the AuthN and AuthZ platform, defining and evangelizing organizational standards and best practices while designing and implementing highly reliable and scalable systems, and mentoring Senior and Staff engineers to raise the technical bar. Key Responsibilities Drive Technology Vision & Roadmap: Define and champion a 12–18 month platform strategy, author and approve RFCs, and align cross-functional teams toward shared objectives. Architectural Authority: Provide thought leadership in designing AuthN and AuthZ architectures for multi-region, multi-tenant environments. Establish and enforce API governance standards and controlling access, monitoring with detection and response. Lead Complex System Design: Oversee architecture that ensures backward compatibility, orchestrates phased migrations, and maintains data integrity—including eventual consistency—while optimizing caching strategies. Operational Excellence & Reliability: Set and uphold SLOs and error budgets. Lead capacity planning, performance optimization, and incident management, including root-cause analysis and postmortem reviews. Security, Compliance & Cost Optimization: Ensure privacy and regulatory compliance while driving cost-efficient technical decisions and operational standards. Hands-on Contribution: Perform high-impact code reviews and performance optimizations. Cross-Functional Influence: Partner with PMs, TPMs, and teams across Search, Data, Checkout, and more to deliver reusable platform components and standards. Mentorship & Bar Raising: Coach Senior and Staff level engineers, lead design reviews, and elevate engineering culture and quality standards. Basic Qualifications 10+ years of professional backend development experience (excluding internships) 7+ years of experience in Java/Kotlin/Spring-based service development and 3+ years in architecture leadership Proven experience designing and operating web-scale microservices; hands-on experience with AWS and Kubernetes Deep expertise in diagnosing mission-critical system failures, identifying root causes, and institutionalizing preventive measures Strong communication and leadership skills to align stakeholders and drive complex technical decisions across organizations Preferred Qualifications Proven experience designing and operating AuthN and AuthZ infrastructure and services – access control, monitoring, detection, and response. Experience designing and operating large-scale distributed systems handling global multi-region traffic Hands-on experience with data pipelines and event processing using Kafka, Spark, Cassandra, and Airflow Proven track record in building observability frameworks with tools such as OpenTelemetry, Prometheus, and Grafana Expertise in JVM performance tuning, large-scale cache/storage design, API schema versioning, and testing Experience designing platforms, frameworks, or SDKs that are widely adopted across multiple product teams 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/