Staff Back-end Engineer [L6-1] (NCA Services)

The role

You will participate in and lead the evolution of the advertising system towards an AI-first direction. This includes designing core advertising systems, building infrastructure for AI model training, and delivering end-to-end AI/ML systems.

What you will do

• Participate in the architectural design and iterative optimization of core NCA advertising systems including bidding, ranking, and serving
• Design and build infrastructure to support AI model training and evaluation including data generation, simulation environments, and experimental frameworks
• Lead end-to-end delivery of key AI/ML systems covering offline training, online serving, A/B testing, and effectiveness evaluation
• Drive systematic AI-first transformation of core advertising system modules

Required qualifications

• Background in Computer Science, Mathematics, Statistics, or related fields with solid theoretical foundations
• Rigorous thinking with the ability to deliver from problem definition to business results
• Continuous curiosity and fast learning ability regarding AI/ML technology
• Proficiency in using AI programming tools such as Cursor, Copilot, or Claude Code to improve development efficiency
• Ability to evaluate and review the quality of AI-generated code
• Proficiency in Java/Python
• Experience in large-scale distributed system design and deployment
• Understanding of asynchronous, concurrency, idempotency, and rate limiting
• Familiarity with mainstream deep learning frameworks
• Understanding of training and deployment principles for advertising ML models such as CTR/CVR prediction and ranking
• Experience in designing and optimizing low-latency online inference systems

Nice to have

• Experience in advertising systems or recommendation systems
• Experience in advertising bidding, budget optimization, or ROAS related projects
• Experience leading cross-team technical solutions to drive complex dependency projects

About the company

Coupang is one of the world's largest and fastest-growing e-commerce platforms. It is a global company with offices in Beijing, Los Angeles, Seattle, Seoul, Shanghai, and Silicon Valley.