Senior Staff Backend Engineer

About this role

<p><strong><span data-contrast="auto">Company Introduction</span></strong><span data-contrast="auto"> </span><span data-ccp-props="{"134233279":true,"134245417":false}"> </span></p> <p><span data-contrast="auto">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. </span><span class="Apple-converted-space"> </span><span data-ccp-props="{"134233279":true,"134245417":false}"> </span></p> <p><span data-contrast="none">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.</span><span class="Apple-converted-space"> </span><span data-ccp-props="{"134233279":true,"134245417":false}"> </span></p> <p><span data-contrast="auto">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. </span><span data-ccp-props="{"134233279":true,"134245417":false}"> <br></span><span data-contrast="auto"> </span><span data-ccp-props="{"134233279":true,"134245417":false}"> </span></p> <p><strong><span data-contrast="auto">Role Overview</span></strong></p> <p><span data-ccp-props="{"134245417":false}"><br></span>We're looking for a Senior Staff Engineer to lead the technical direction of MyCoupang, Coupang's post-purchase customer experience platform. Every order tracking, delivery, return, payment, and support interaction for tens of millions of active customers across Korea and Taiwan flows through this system. </p> <p>MyCoupang operates at significant scale: ~34,000 requests per second, ~2.4 billion requests daily, and ~16 billion weekly, served by 700+ production pods with a 9x daily traffic swing that must be absorbed seamlessly. The platform delivers P95 latency under 500ms, P99 under 1 second, and maintains a 0.002% error rate. Built on Kotlin (backend), TypeScript with server-side rendering and ReactJS (frontend), the system spans a dual-service architecture with 100+ page routes and 30+ business domains including Orders, Payments, Delivery, Cancel/ Return/Exchange, WOW Membership, Travel, and Contact Center.</p> <p>The team ships 100+ features monthly, supports multi-market business logic across KR and TW (each with region-specific compliance, internationalization, and payment methods), and enforces security through a 4-phase authorization pipeline. This is a complex, high-stakes environment where architectural decisions have immediate customer impact.</p> <p><strong><span data-contrast="auto">What You Will Do</span></strong><strong> </strong><span data-contrast="none"><span data-ccp-charstyle="normaltextrun"><br></span></span><span data-contrast="none"><span data-ccp-charstyle="eop" data-ccp-charstyle-defn="{"ObjectId":"920dbcde-2834-5e15-a5fa-062170b236ba|1","ClassId":1073872969,"Properties":[201342446,"1",201342447,"5",201342448,"3",201342449,"1",469777841,"맑은 고딕",469777842,"Arial",469777843,"新細明體",469777844,"맑은 고딕",201341986,"1",469769226,"맑은 고딕,Arial,新細明體",268442635,"24",469775450,"eop",201340122,"1",134233614,"true",469778129,"eop",335572020,"1",469778324,"Default Paragraph Font"]}"> </span></span><span data-ccp-props="{"134245417":true,"201341983":0,"335559740":259}">In this role, you will own the most critical technical challenges on the platform: designing multi-market abstractions that scale to new regions, driving the system toward 99.99% availability, leading disaster recovery readiness and capacity planning across the full production fleet, and defining the long-term architecture for a platform that must reliably serve billions of requests weekly while continuing to evolve. You will directly influence customer retention and satisfaction metrics for every Coupang post-purchase…