Principal Software Engineer, Build Platform

Every day, tens of millions of people come to Roblox to explore, create, play, learn, and connect with friends in 3D immersive digital experiences– all created by our global community of developers and creators. At Roblox, we’re building the tools and platform that empower our community to bring any experience that they can imagine to life. Our vision is to reimagine the way people come together, from anywhere in the world, and on any device. We’re on a mission to connect a billion people with optimism and civility, and looking for amazing talent to help us get there. A career at Roblox means you’ll be working to shape the future of human interaction, solving unique technical challenges at scale, and helping to create safer, more civil shared experiences for everyone. As a Principal Software 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. For roles that are based at our headquarters in San Mateo, CA: The starting base pay for this position is as shown below. The actual base pay is dependent upon a variety of job-related factors such as professional background, training, work experience, location, business needs and market demand. Therefore, in some circumstances, the actual salary could fall outside of this expected range. This pay range is subject to change and may be modified in the future. All full-time employees are also eligible for equity compensation and for benefits as described on this page. Annual Salary Range $345,040—$399,420 USD Roles that are based in an office are onsite Tuesday, Wednesday, and Thursday, with optional presence on Monday and Friday (unless otherwise noted). Roblox provides equal employment opportunities to all employees and applicants for employment and prohibits discrimination and harassment of any type without regard to race, color, religion, age, sex, national origin, disability status, genetics, protected veteran status, sexual orientation, gender identity or expression, or any other characteristic protected by federal, state or local laws. Roblox also provides reasonable accommodations to candidates with qualifying disabilities or religious beliefs during the recruiting process. For US based roles only, please note the Company may not be able to employ candidates for this role who have United States work authorization related to certain U.S. visa categories, or support future H-1B sponsorship at this time.