Senior Backend Engineer

PLAY, GROW and WIN

To be a part of Virtuos means to be a creator.

At Virtuos, we harness the latest technologies to make games better and more immersive than ever before. That is why we pride ourselves in constantly pushing the boundaries of possibility since our founding in 2004.

Virtuosi is a team of experts - people who have come together to share their mutual passion for making and playing games. People with the same enthusiasm for exploring new ideas and the constant drive to excel in their field. People who believe in earning success through dedication.

At Virtuos, we are at the forefront of gaming, creating exciting new experiences daily. Join us to Play, Grow and Win - together.

ABOUT THE POSITION

We are looking for a Senior Backend Engineer to design, develop, and maintain backend services and AI-powered applications. You will deliver new features, integrate AI capabilities, and improve the reliability, performance, and maintainability of existing systems.

This is a senior, hands-on individual contributor role. You will write code, contribute to architectural decisions, and collaborate with cross-functional teams to turn product requirements and emerging AI capabilities into production-ready solutions.

Backend Development and Maintenance

• Build and maintain scalable Python services and secure RESTful APIs using FastAPI.
• Own features from technical design and implementation through testing, deployment, and ongoing support.
• Extend existing applications, troubleshoot production issues, refactor code, and manage dependency upgrades while preserving API compatibility.
• Design and optimize database access, caching, and asynchronous processing.
• Implement authentication, authorization, input validation, and reliable error handling.

AI Application Development

• Integrate LLMs and other AI services through provider APIs and SDKs, creating reusable interfaces for application teams.
• Design reliable APIs and tool interfaces for AI applications, with well-defined input/output schemas, validation, and error handling.
• Develop AI workflows using prompt orchestration, structured outputs, tool calling, and streaming responses.
• Manage context limits, rate limits, timeouts, retries, and provider failures to support reliable production use.
• Evaluate model and prompt changes against representative test cases, balancing output quality, latency, and cost.
• Design and develop multi-agent systems and workflows, where appropriate, to address business requirements and automate complex tasks.

Quality Delivery and Collaboration

• Write automated tests and maintain regression coverage for backend services and AI integrations.
• Improve logging, metrics, and tracing to diagnose failures and monitor service performance and AI usage.
• Maintain CI/CD pipelines and containerized deployments in collaboration with infrastructure teams.
• Conduct code reviews, document technical decisions, and mentor junior engineers.
• Partner with product, frontend, AI, and infrastructure teams to clarify requirements and deliver maintainable solutions.

Must Have

• 5+ years of professional backend development experience, including 2+ years developing AI-powered applications or services, with demonstrated ownership of service design, production deployment, and ongoing maintenance.
• Strong Python and FastAPI expertise, including asynchronous programming, type annotations, Pydantic, dependency injection, and RESTful API design.
• Practical experience integrating AI APIs or SDKs, including prompt design, structured outputs, and streaming or asynchronous workflows.
• Understanding of common LLM challenges, including context management, hallucinations, prompt injection, rate limits, and token costs.
• Hands-on public cloud experience, such as AWS, Azure, or GCP, including deploying and operating backend applications.
• Solid database skills with PostgreSQL or another relational database, including data modeling and query optimization.
• Working knowledge of secure API design, authentication and authorization, and secrets management.
• Experience designing reliable backend services and external API integrations, including concurrency control, timeouts, retries, idempotency, and rate limiting, with the ability to explain design tradeoffs.
• Experience with pytest or equivalent testing tools, Git, CI/CD, and Docker.
• Strong problem-solving skills and the ability to independently navigate, extend, and improve an existing codebase.
• Strong written and verbal communication skills in both English and Chinese, with the ability to explain technical decisions and tradeoffs across teams.

Nice to Have

• AWS experience, particularly with S3, SageMaker, DynamoDB, ECS, CloudWatch, or Secrets Manager.
• Frontend development experience with Vue or React, including TypeScript or JavaScript.
• Experience with agent frameworks such as LangGraph, Pydantic AI, Claude Agent SDK, or comparable tools, including multi-agent orchestration, task delegation, and context sharing.
• Experience with retrieval-augmented generation (RAG), embeddings, and vector databases such as pgvector.
• Experience deploying local or self-hosted LLMs using tools such as vLLM, Ollama, or llama.cpp.
• Experience with multimodal AI, including image, audio, or 3D generation.