Senior Backend Engineer (Python, AI Applications)

About the role

Virtuos, a video game developer founded in 2004 and headquartered in Singapore, is looking for a Senior Backend Engineer to design, develop and maintain backend services and AI-powered applications. This is a senior, hands-on individual contributor role: you will write code, contribute to architectural decisions and work with product, frontend, AI and infrastructure teams to turn requirements and emerging AI capabilities into production-ready solutions.

Key responsibilities

• Build and maintain scalable Python services and secure RESTful APIs with FastAPI, owning features from design through testing, deployment and support
• Extend applications, troubleshoot production issues, refactor code and manage dependency upgrades while keeping API compatibility
• Design and optimize database access, caching and asynchronous processing, and implement authentication, authorization, input validation and error handling
• Integrate LLMs and AI services via provider APIs and SDKs, building reusable interfaces with defined input/output schemas
• Develop AI workflows using prompt orchestration, structured outputs, tool calling and streaming responses, and manage context, rate, timeout and retry limits
• Design multi-agent systems and workflows where appropriate, and evaluate model and prompt changes against test cases
• Write automated tests and maintain regression coverage, and improve logging, metrics and tracing
• Maintain CI/CD pipelines and containerized deployments, conduct code reviews, document technical decisions and mentor junior engineers

Required profile

• 5+ years of professional backend development, including 2+ years on AI-powered applications, with ownership of service design, deployment and maintenance
• Public cloud experience (AWS, Azure or GCP) and strong database skills with PostgreSQL or another relational database
• Experience with secure API design, authentication, authorization and secrets management
• Experience with pytest, Git, CI/CD and Docker; strong problem-solving and communication skills in English and Chinese

Required skills

• Python and FastAPI, including async programming, type annotations, Pydantic and dependency injection
• Practical experience integrating AI APIs and SDKs, with understanding of LLM challenges such as context management, hallucinations and prompt injection
• Nice to have: AWS (S3, SageMaker, DynamoDB, ECS, CloudWatch, Secrets Manager), Vue or React with TypeScript, agent frameworks (LangGraph, Pydantic AI, Claude Agent SDK), RAG, vector databases (pgvector), self-hosted LLMs (vLLM, Ollama, llama.cpp) and multimodal AI

What we offer

• A role in the headquarters and the R&D center working with cutting-edge gaming technology
• Group outings and activities, comprehensive medical healthcare and relocation support
• Career and international mobility opportunities, an internal mobility program and learning opportunities