Principal AI Infrastructure Engineer, Build Platform

As a Principal AI Infrastructure Engineer on the Build Platform team, you will set the technical direction for the infrastructure behind AI-powered creation on Roblox. Build lets anyone make a game by describing it, on mobile and in Studio. Our team owns the platform underneath: the cloud-hosted agent harness, tools and skills, and evaluation framework. You'll be the senior technical leader shaping its architecture.

This role spans the full agent stack: orchestrating long-running, multi-step workflows; model integration and routing across providers; tool and skill execution; sandboxed game environments; evals at scale; and the reliability, safety, and cost systems that let us grow to millions of creators.

You Have:

• 8+ years of experience building and operating large-scale distributed systems, including technical leadership across multiple teams.
• Deep experience designing backend platforms used by other engineering teams.
• Hands-on experience with production AI/ML systems, such as model serving, orchestration, LLM integration, or agentic execution loops (planning, tool use, recovery, long-running workflows).
• A strong understanding of tool and skill design and structured evaluation for AI systems.
• The judgment to weigh tradeoffs and make pragmatic calls under ambiguity.
• A BS in Computer Science or a related field, or equivalent professional experience.

You Are:

• Excited to define how AI agents create at scale, and to stay hands-on while doing it.
• A clear communicator who can explain complex technical direction to engineers, product, and leadership.
• Experienced with workflow engines (e.g., Temporal), multi-provider model routing, or AI cost management (bonus).

You Will:

• Own the technical architecture and long-term roadmap for the Build agent platform.
• Design for reliability, safety, observability, and cost efficiency in production AI workloads, including usage metering and model-routing strategy.
• Define how we measure agent quality and build the evaluation infrastructure that drives model, prompt, and skill decisions.
• Partner with Build product teams, ML infrastructure, and Safety to ship new capabilities quickly and safely.
• Raise the engineering bar through design reviews, mentorship, and hands-on technical leadership.