Sr. Staff Back-end Engineer (Coupang Pay)

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 ecommerce 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 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   Coupang Pay, a fintech subsidiary of Coupang Corp, provides payment gateway services for our growing and diverse business and customers. We focus on providing innovative payment and financial service solutions to all people and businesses that use Coupang’s platforms, ranging from the customers who make a purchase on coupang.com and use Coupang Eats service, the merchants who sell on Coupang’s open market platform, and the restaurants that use Coupang Eats delivery service. Coupang Pay strives to innovate all our customers’ payment-related experiences with the team members who have the most diverse fintech experiences and have a good understanding of Coupang’s business.   Why Coupang Pay?   * Shape the future of digital payments in one of the world’s fastest-growing e-commerce ecosystems. * Own mission-critical systems serving millions of customers at global scale. * Work in an inclusive, high-impact culture that values innovation, speed, and craftsmanship. * Competitive compensation, equity, benefits, and continuous learning opportunities.   Key Responsibilities   We are seeking a Sr. Staff Back-end Engineer who is both a visionary technical leader and a hands-on builder. This role combines architectural ownership, full-stack development, and distributed systems expertise to deliver payment systems with industry-leading scale, resiliency, and speed.   In this role, you will lead the technical roadmap and define FinTech Lending products from the ground up. Your system will directly power the financial health of millions of consumers and small business sellers across multiple Asian markets.   Hands-on Architecture & Development * Architect, design, and implement complex, distributed, cloud-native systems spanning frontend, backend, APIs, data pipelines, and infrastructure. * Write and review production-grade code; optimize critical paths for performance, reliability, and correctness. * Lead by example in code quality, observability, CI/CD, and security. Operate at Scale & Speed * Deliver mission-critical features to millions of users with rapid iteration while maintaining high availability and data integrity. * Optimize systems for concurrency, throughput, and cost efficiency under heavy global loads. * Participate in on-call rotation and drive continuous improvements in reliability and incident prevention. Full-Stack & Distributed Systems Leadership * Own large-scale payment microservices, event-driven pipelines, caching systems, and real-time APIs. * Guide teams across web/mobile frontends, middleware, and backend services to ensure cohesive and performant experiences. * Spearhead adoption of best practices in distributed computing, fault tolerance, and multi-region scaling. Innovation & Emerging Technology * Drive adoption of AI/ML technologies—build or integrate AI agents and intelligent automations into payment workflows. * Stay ahead of fintech innovation, evaluating and deploying new technologies to improve customer experience and system resilience. Leadership & Mentorship * Mentor senior engineers and Sr.Staff-level peers, fostering a culture of innovation, technical rigor, and rapid delivery. * Collaborate cross-functionally with product, design, and infrastructure leaders to shape both technical vision and product strategy.   Basic Qualifications * Bachelor’s degree in Computer Science, Software Engineering, or related field. * 15+ years of software engineering experience, with proven success in large-scale distributed systems * Deep expertise in full-stack development (Java, Go, Python, JavaScript/TypeScript, or equivalent) and core payment systems. * Hands-on architecture and design experience with microservices, event-driven systems, APIs, and real-time data processing. * Strong fundamentals in algorithms, data structures, concurrency, and system design. * Proven ability to deliver rapidly and reliably in fast-paced, high-growth environments   Preferred Qualifications * Master’s or PhD in Computer Science or related technical discipline. * Payment systems experience at top global fintech companies. * Experience in high-scale ledgering and transaction engines. * Experience in credit risk and real-time decisioning system. * Experience in core lending platform lifecycle. * Experience in cloud infrastructure and resiliency (99.999% availability). * Experience in financial security, compliance and API openness. * Deep knowledge of distributed microservices, cloud-native architectures (Kubernetes, containerization, serverless), and multi-region scaling. * Experience in dealing with and resolving the issues that occur when an organization grows and the systems get complicated * Publications, patents, or open-source contributions in distributed systems, payments, or AI applications. * Fluent English (Korean a plus); strong communication skills with global 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.

Coupang

Coupang is reimagining the shopping experience with the goal of wowing each customer from the instant they open the Coupang app to the moment an order is delivered to their door. Powered by an outstanding end-to-end e-commerce and logistics network and a fanatical culture of customer centricity, Coupang has broken tradeoffs around speed, selection, and price. Today, we provide exceedingly fast shipping speeds on millions of items including fresh groceries, delivered within hours nationwide, 365 days a year. We are doing this for millions of consumers in Korea. Korea is home to one of the largest and fastest growing e-commerce opportunities anywhere in the world.  We have been named as one of the ‘50 Smartest Companies in the World’ by MIT Technology Review, and as one of Forbes magazine’s ‘30 Global Game Changers.’ In 2020, we placed second on CNBC’s ‘Disruptor 50’ list.    JOB OVERVIEW   Coupang Pay is transforming the digital payments experience at massive scale—powering millions of secure transactions every day across Coupang.com, Coupang Eats, and our ecosystem of merchants and partners. We are building fast, reliable, and innovative fintech solutions that serve both consumers and businesses across Korea and beyond. We are seeking a Sr.Staff Software Engineer who is both a visionary technical leader and a hands-on builder. This role combines architectural ownership, full-stack development, and distributed systems expertise to deliver payment systems with industry-leading scale, resiliency, and speed.    KEY RESPONSIBILITIES  Hands-on Architecture & Development  * Architect, design, and implement complex, distributed, cloud-native systems spanning frontend, backend, APIs, data pipelines, and infrastructure.  * Write and review production-grade code; optimize critical paths for performance, reliability, and correctness.  * Lead by example in code quality, observability, CI/CD, and security.  Operate at Scale & Speed  * Deliver mission-critical features to millions of users with rapid iteration while maintaining high availability and data integrity.  * Optimize systems for concurrency, throughput, and cost efficiency under heavy global loads.  * Participate in on-call rotation and drive continuous improvements in reliability and incident prevention.  Full-Stack & Distributed Systems Leadership  * Own large-scale payment microservices, event-driven pipelines, caching systems, and real-time APIs.  * Guide teams across web/mobile frontends, middleware, and backend services to ensure cohesive and performant experiences.  * Spearhead adoption of best practices in distributed computing, fault tolerance, and multi-region scaling.  Innovation & Emerging Technology  * Drive adoption of AI/ML technologies—build or integrate AI agents and intelligent automations into payment workflows.  * Stay ahead of fintech innovation, evaluating and deploying new technologies to improve customer experience and system resilience.  Leadership & Mentorship  * Mentor senior engineers and Sr.Staff-level peers, fostering a culture of innovation, technical rigor, and rapid delivery.  * Collaborate cross-functionally with product, design, and infrastructure leaders to shape both technical vision and product strategy.    QUALIFICATIONS  * Bachelor’s degree in Computer Science, Software Engineering, or related field.  * 12–15+ years of software engineering experience, with proven success in large-scale distributed systems.  * Deep expertise in full-stack development (Java, Go, Python, JavaScript/TypeScript, or equivalent).  * Hands-on architecture and design experience with microservices, event-driven systems, APIs, and real-time data processing.  * Strong fundamentals in algorithms, data structures, concurrency, and system design.  * Proven ability to deliver rapidly and reliably in fast-paced, high-growth environments.    PREFERRED QUALIFICATIONS  * Master’s or PhD in Computer Science or related technical discipline.  * Payment systems experience at top global fintech companies (e.g., Stripe, PayPal, Razorpay, JusPay, AliPay, Visa, Adyen, Square, Mastercard).  * Hands-on experience building and deploying AI Agents (GenAI, RAG, workflow automation, LLMs) into production-scale systems.  * Deep knowledge of distributed microservices, cloud-native architectures (Kubernetes, containerization, serverless), and multi-region scaling.  * Experience in dealing with and resolving the issues that occur when an organization grows in size and the systems get complicated  * Publications, patents, or open-source contributions in distributed systems, payments, or AI applications.  * Fluent English (Korean a plus); strong communication skills with global stakeholders.    WHY COUPANG PAY?  * Shape the future of digital payments in one of the world’s fastest-growing e-commerce ecosystems.  * Own mission-critical systems serving millions of customers at global scale.  * Work in an inclusive, high-impact culture that values innovation, speed, and craftsmanship.  * Competitive compensation, equity, benefits, and continuous learning opportunities.    JOIN US TO BUILD THE CORE OF NEXT-GENERATION FINTECH AT SCALE.        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.  * Those eligible for employment protection (recipients of veteran’s benefits, the disabled, etc.) may receive preferential treatment for employment in accordance with applicable laws.  * We are proud to offer equal opportunities for all applicants. * Hiring may be restricted in case the legal qualifications required for hiring and work performance is not met. * 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. * This is a full-time regular position and includes 12 weeks of probation period; provided, however, the probationary period may be either skipped, shortened or extended if necessary for business purposes.    Privacy Notice  * Your personal information will be collected and managed by Coupang as stated in the Application Privacy Notice is located below.  https://privacy.coupang.com/en/land/jobs/    Document Return Policy  1. This notification is given pursuant to Article 11 (6) of the Fair Hiring Procedure Act. 2. 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. 3. 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 It by email (recruitingops@coupangpay.com). 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. 4. 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 his/her hiring documents will be destroyed immediately in accordance with the Personal Information Protection Act. 5. The above paragraphs 1 - 4 shall only apply when the labor-related laws of Korea govern the application. They are otherwise not applicable.

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. 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 You will lead the architectural vision for our next-generation data centers, transitioning our global footprint from traditional colocation models to high-density AI Factories. You are responsible for the physical and logical blueprint of the facility—ensuring that our "white space" can support 100kW+ racks, liquid-to-chip cooling, and the massive throughput requirements of 800G/1.6T networking. Responsibilities * Facility Strategy: Design the "Basis of Design" (BOD) for hyperscale facilities, including site selection, building massing, and modular "pod" scalability. * Thermal Management: Architect the transition from air-cooled data halls to Hybrid Cooling environments (Direct-to-Chip, Rear Door Heat Exchangers, and Immersion Cooling) to support high-TDP AI chips. * Power & Energy: Partner with electrical engineers to design high-availability power chains (N+1/2N) capable of supporting 50MW+ of IT load per hall. Evaluate the integration of Small Modular Reactors (SMRs) or hydrogen fuel cells for onsite power. * Network & Fabric Topology: Define the physical layout for OSFP-based high-radix fabrics. Optimize cabling pathways and "meet-me-room" designs to minimize signal degradation for InfiniBand and RoCE v2 compute planes. * Modular Construction: Drive the adoption of modular "skid-based" deployments to accelerate construction timelines by 30% without sacrificing reliability or efficiency (PUE). * Sustainability & ESG: Ensure designs meet 2026 carbon-neutrality standards by implementing waste-heat reuse for local district heating and optimizing Water Usage Effectiveness (WUE).  Qualifications * Education  * B.Tech/M.S. or Ph.D. in Computer Science, Electrical Engineering, or a related field (or equivalent industrial experience) *  Required Technical Expertise * Physical Infrastructure: Deep understanding of rack densities (moving from 15kW to 100kW+), busways, and floor loading for heavy liquid-cooled systems * Hardware Lifecycle: Mastery of the latest server form factors, including E1.S/E3.S storage and the mechanical requirements of NVIDIA Blackwell/Rubin rack systems * Networking Standards: Expert knowledge of the physical layer (OSFP/QSFP-DD), fiber types (OM5/Single-mode), and OSPF/BGP routing at the facility scale * BIM & Digital Twin: Proficiency in Revit, AutoCAD, and Digital Twin platforms to simulate airflow, power distribution, and maintenance accessibility before breaking ground * Preferred Qualifications * 10+ years in mission-critical facility design or lead architectural roles at a Hyperscaler (AWS, Google, Meta) or Tier-1 Provider (Equinix, Digital Realty) * Expertise in Uptime Institute Tier Standards and LEED Platinum certifications * Experience with "AI-driven DCIM" (Data Center Infrastructure Management) tools for predictive maintenance * Domain Skills Needed * Cooling: Direct-to-Chip (DLC), CDU Integration, Water-Side Economizers * Compute: GPU Cluster Architecture, DPU Integration (BlueField) * Network: 800G/1.6T OSFP Optics, Fiber Density, OSPF Routing * Storage: NVMe-over-Fabrics (NVMe-oF), E1.S EDSFF * Construction: Modular Design, Prefabricated Power Skids, BIM Recruitment Process and Others * Recruitment Process  1. Application Review - Phone Interview - Onsite (or Virtual Onsite) Interview – Offer  2. The exact nature of the recruitment process may vary according to the specific job and may be changed due to scheduling or other circumstances.  3. Interview schedules and the results will be informed to the applicant via the e-mail address submitted at the application stage.  * Things to Consider  1. This job posting may be closed prior to the stated end date for application if all openings are filled.     2. 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.     3. Coupang does not discriminate against disabled applicants or those with veteran status. We are proud to offer equal opportunities for all applicants.  * Privacy Notice  1. Your personal information will be collected and managed by Coupang as stated in the Application Privacy Notice located HERE.  * Document Return Policy  1. This notification is given pursuant to Article 11 (6) of the Fair Hiring Procedure Act.   2. 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.  3. 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 by email (recruitingops@coupang.com) 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.  4. 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.  5. The above paragraphs 1 - 4 shall only apply when the labor-related laws of Korea govern the application. They are otherwise not applicable. Equal Opportunities for All Coupang is an equal opportunity employer. Our unprecedented success could not be possible without the valuable inputs of our globally diverse team.