Sr. Staff Back-end Engineer (Coupang Pay)

The role

This role is a visionary technical leader and hands-on builder who will architect, design, and implement complex, distributed, cloud-native systems. You will own large-scale payment microservices and drive the adoption of AI/ML technologies into payment workflows.

What you will do

• Architect, design, and implement complex, distributed, cloud-native systems.
• Write and review production-grade code.
• Optimize critical paths for performance, reliability, and correctness.
• Lead in code quality, observability, CI/CD, and security.
• Deliver mission-critical features to millions of users.
• Optimize systems for concurrency, throughput, and cost efficiency.
• Participate in on-call rotation.
• Own large-scale payment microservices, event-driven pipelines, caching systems, and real-time APIs.
• Guide teams across web/mobile frontends, middleware, and backend services.
• Mentor senior engineers and Sr.Staff-level peers.

Required 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

Nice to have

• 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)

Benefits

• Competitive compensation
• Equity
• Benefits
• Continuous learning opportunities

Before you apply

• The recruitment process includes Application Review, 1st Interview, Virtual Onsite Interviews, and Offer.
• 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.

About the company

Coupang Pay focuses on delivering innovative payment and financial services solutions to users of the Coupang app. The fintech business is reimagining financial services for consumers and sellers in Korea and Taiwan.