Kotlin Backend Engineer

TL;DR: We're looking for exceptional builders who help us design and ship the foundational infrastructure that lets Conduct scale to the world's largest enterprises, while accelerating the product teams building on top of it. WHY CONDUCT The world's largest companies are slowed down by the software they run on. We’re building the AI operating system that absorbs IT complexity and unlocks entirely new levels of speed, output, and ambition. We believe this is a generation-defining mission. Major enterprises already trust us with their most critical systems, we just closed a $60M Series A from top-tier funds, and we're still early enough that what you build here defines the company. We're a small, talent-dense team doing our life's work at Conduct - we value extreme ownership, high velocity, and low-ego collaboration. If you bring that same drive, we will make sure this is the place you do yours too.   WHO WE HIRE We're looking for pragmatic, high-agency engineers who thrive in ambiguity and care as much about the system as the feature. Fundamentals matter more to us than familiarity with any specific tool. If you're strong, you'll pick it up fast. You'll stand out if you: * Have 3+ years of backend experience with exposure to platform or infrastructure work. You have seen what it actually takes to go from MVP to scalable, production-grade systems * Have strong system design instincts and own problems end-to-end across APIs, infrastructure, and data flows * Are experienced with distributed systems, scaling databases (postgres), queueing, and large-scale batch processing * Understand how to benchmark and tune systems under real load, and know how to make pragmatic trade-offs when the data is ambiguous * Are familiar with LLM infrastructure at scale * Raise the bar around you — through code, mentorship, and better systems — and fix problems without waiting for permission   WHAT YOU’LL OWN You'll have broad ownership across architecture, developer experience and production systems. The infrastructure problems are real and genuinely hard: we process tens of millions of lines of code per customer, generating large-scale LLM workloads under enterprise-grade reliability requirements. You'll work on the systems that keep product teams fast and unblocked and that hold up as we onboard some of the largest companies in the world. In practice that means: * Accelerating product teams. You build the platform that lets engineers focus on product, not plumbing: shared abstractions, sensible defaults, internal tooling that compounds. * Scaling with confidence. You design and maintain infrastructure that meets stringent enterprise reliability requirements and doesn't become fragile as we grow. * Taming LLM infrastructure. High token throughput, real-time usage, flaky providers — you make it reliable. * Raising the floor, not just the ceiling. From auth to observability to job orchestration, you build systems that are well-designed from the start and don't need to be rebuilt later.   OUR STACK Our stack prioritises what matters: shipping to customers—fast—without compromising on quality and engineering. Fundamentals are more important to us than familiarity with any technology or tool: if you're strong, we’re sure you'll pick it up fast. Here’s our setup: * React, Vite, TanStack frontend * Kotlin backend: Modern and expressive, paired with the maturity, tooling, and depth of the Java ecosystem. Lets us ship fast now without painting ourselves into a corner later. * Temporal and PortKey: Absorbs infrastructure complexity around durable execution and enterprise-compliant LLM routing, so we can focus on shipping instead. * Specialised LLM Harness: Built from hard-earned experience to give agents maximum freedom and intelligence without compromising on enterprise control, governance, or reliability.

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.    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 Overview 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.  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. 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. What You Will Do  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 interaction, set the engineering bar for the team, and shape the technical strategy for one of Coupang's most customer-facing systems. Basic Qualifications  * Minimum 12 years of experience working on software design and development in Java. * Hands-on experience with designing, building, and deploying scalable, high available systems * Experience with high-throughput, low-latency systems handling millions of requests * Experience with event-driven architectures using Kafka or similar messaging systems * Strong problem-solving skills and ability to debug complex distributed systems * Excellent collaboration skills to work with cross-functional teams (Product, CS, Logistics, Payment) Preferred Qualifications   * Backend development (Java, Kotlin, or similar JVM languages preferred) * RESTful API design and implementation * Database design and optimization (MySQL, * Aurora)Message queue systems * (Kafka)Workflow engines (Activiti BPMN, Temporal) * Monitoring and alerting (Grafana, CloudWatch) * Version control * (Git)CI/CD tools (CircleCI or similar   Type of work model  * Hybrid Details to consider  * 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. https://privacy.coupang.com/en/land/jobs/