Principal Machine Learning Engineer (Alt Defense)

Location: United States; roles based in the San Mateo, California headquarters are onsite Tuesday, Wednesday, and Thursday, with optional presence on Monday and Friday.

Company

Roblox operates a platform for creating and experiencing 3D immersive digital worlds and focuses on safe, civil, and inclusive online communities.

What you will do

• Lead the technical vision for an alternate account detection platform that enables proactive, near real-time prevention.
• Architect high-scale machine learning systems using graph neural networks and advanced clustering across billions of entities.
• Solve ground-truth and training-data challenges for adversarial use cases.
• Build low-latency, high-throughput detection systems that identify returning bad actors within minutes.
• Develop adversarial approaches and use behavioral signals to improve detection precision and recall.
• Mentor machine learning and software engineers while driving the technical roadmap.

Requirements

• MS or PhD in Computer Science, Machine Learning, or a related field.
• 10+ years of industry experience in applied machine learning, with significant experience in anti-abuse, fraud, integrity, or identity.
• Deep expertise in large-scale graph neural networks, including GraphSAGE and related graph-learning methods.
• Experience with unsupervised or semi-supervised clustering at the scale of billions of nodes.
• Track record of leading complex technical projects from conception through production deployment.
• Experience deploying machine learning models in high-throughput, low-latency environments and designing defenses against evolving adversarial behavior.

Culture & Benefits

• Full-time employment with equity compensation and employee benefits.
• Work within the Safety organization on systems that protect Roblox users and developers.
• Collaborative environment focused on technical excellence, mentorship, rapid iteration, and responsible product decisions.
• Equal employment opportunity and reasonable accommodations during the recruiting process.
• Future H-1B sponsorship may not be supported for US-based roles, and employment may be unavailable for certain US visa categories.