Senior Backend Engineer

We are helping our client, publicly traded global AI product company (HQ in USA), expand its engineering team in Seoul. The company develops advanced AI-powered solutions that combine AI models, real-time interaction and digital technology to create personalised conversational experiences. The company is growing rapidly, with its products are already deployed internationally and used in production at scale, while the company continues to grow and actively develop its technology and product capabilities. In this role, you will join the core engineering team in Seoul and take ownership of the development, architecture and end-to-end delivery of key components of the company's core AI product. You will contribute throughout the development lifecycle, from architecture and design through deployment and ongoing optimisation. This is a critical hands-on role, focused on AI inference optimization, latency reduction, and scalable API design, enabling efficient real-time communication between server and web systems, across complex distributed systems from design to production Tech stack includes (approx. 70% backend / 30% frontend) Python (Flask / FastAPI / Litestar), React or Svelte with real-time interactions across Web, Unity, and AI modules via WebSockets and SSE Responsibilities Own core systems and services development end to end, from architecture and data modelling through development, deployment, scaling and production operation.Evolve the core platform architecture to improve scalability, performance and maintainability across distributed AI systems.Identify and refactor critical areas of the technology stack to improve production performance, reliability and scalability.Drive AI inference and latency optimisation to support responsive, real-time user experiences.Contribute to engineering standards and code reviews, helping maintain high-quality, maintainable code across the team.Qualifications 4–5+ years of SW engineering experience, including hands-on responsibility across development, architecture, deployment and production systems.Strong Python backend development experience using Flask, FastAPI, Litestar and/or comparable Python frameworks.Experience with AWS, GCP and/or Azure, Docker and production system deployment.Strong understanding of distributed systems, client-server architecture and real-time communication using WebSockets and/or SSE.Experience with databases and data modelling using technologies such as PostgreSQL, MySQL, MongoDB, Redis or Memcached, including scalable schema design.Exposure to frontend technologies such as React, Svelte and/or WebAssembly.Conversational English for day-to-day collaboration with international colleagues.Nice to have Experience with complex integrations across Web, Unity and AI components.Experience integrating AI services and optimising inference latency or production performance.Ability to contribute effectively to technical discussions and engineering decisions across teams. The company is offering a competitive compensation and benefits package, together with the opportunity to join a fast-growing global AI business and work on a product already deployed internationally at scale. You will have meaningful technical ownership and work directly on complex challenges involving AI inference, distributed systems, real-time communication and production performance. The role also provides strong opportunities for technical and professional development while working in an international engineering environment.