Senior Backend Software Engineer

We are helping our client, a publicly traded global AI product company headquartered in the USA, expand its engineering team in Seoul. The company develops advanced AI-powered solutions combining AI models, real-time interaction, and digital technology to create personalised conversational experiences. Its products are already deployed internationally and used in production at scale, and the company continues to grow its global presence while investing in its technology and product capabilities. The Role We are looking for a Senior Software Engineer to join the engineering team in Seoul and take meaningful ownership of the development and delivery of core components of the company's AI product. This is a strongly backend-oriented software engineering role, with the majority of the work focused on Python backend development, scalable API design, distributed systems, AI inference optimisation, latency reduction, and production performance. The product is highly visual and interactive, so exposure to frontend technologies such as React or Svelte is a plus, particularly for understanding how backend architecture and changes can affect the frontend experience. However, frontend expertise is not required, and this is not a frontend-focused position. You will contribute across the development lifecycle, from technical design and implementation through deployment, production operation, optimisation, and continuous improvement. The role provides the opportunity to take ownership of important technical areas and grow your scope of responsibility as the Seoul team continues to expand. 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.3y of solid 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.