Founding AI + Backend Engineer

About the role

• Join Winsen Labs as a founding engineer to build core backend and AI infrastructure from the ground up
• Shape the technical direction and architecture of a new AI-native platform alongside founders
• Own the full stack of system design, implementation, and operational health

What you'll work on

• Design and build robust backend systems with APIs, databases, message queues, and caching layers that handle real-world scale
• Implement concurrency patterns, retry logic, state management, and observability to keep systems reliable
• Integrate and orchestrate large language models, agents, and tool-calling workflows into production systems
• Build structured outputs, retrieval mechanisms, and memory management for AI features
• Create evaluation datasets, regression test suites, trace analysis, and failure investigation processes

What we're looking for

• Deep understanding of backend fundamentals across APIs, databases, queues, concurrency, retries, caching, state management, and observability
• Hands-on experience shipping systems that use LLMs, agents, tool calling, structured outputs, retrieval, memory, and orchestration
• Track record of building evaluation frameworks, regression tests, traces, and workflows for analyzing failures
• Ability to learn unfamiliar business domains, question assumptions, and translate messy requirements into clean technical solutions
• Systems thinking with keen attention to reliability, scalability, failure modes, and architectural decisions
• Strong evidence of capability: a meaningful project portfolio, active GitHub profile, open-source work, or shipped systems you can discuss
• Comfort using AI coding tools such as Cursor, Claude Code, Codex, or Copilot
• Drive to own problems end-to-end, ask good questions, and move fast without constant direction