Senior Machine Learning Engineer, User Behavior

As a Senior Machine Learning Engineer for User Behavior, you will build proactive detection and behavioral intelligence systems that shift how Roblox responds to unsafe behavior. You will own the ML foundation for a new capability at Roblox: identifying users at risk of becoming chronic violators before they escalate, and powering the adaptive consequence systems that give them a real chance to change.

What You Will Do

Define and own the ML vision, architectural strategy, and execution that identify casual violators early before they escalate. Develop and maintain production ML models that translate user behavioral signals into actionable risk intelligence. Build the ML foundation from scratch, including the user feature store, training pipelines, and model evaluation infrastructure.

Why It Might Be a Fit

This is a rare opportunity to build a user-level behavioral intelligence capability that will define how Roblox understands and responds to risk at scale. You will feel a deep sense of responsibility in building systems that directly affect millions of users, especially minors, on one of the world's largest platforms.

Requirements

• 5+ years of experience building and shipping production ML systems at scale
• Hands-on experience with ML classification at scale, including traditional ML models, sequence modeling on user-event data, and/or LLM-based approaches
• Proficiency designing and maintaining feature pipelines and feature stores for behavioral or event-driven data
• Experience building embedding-based retrieval systems (ANN / vector search) in production
• Experience building and operating end-to-end ML pipelines: training, offline evaluation, A/B experiment hooks, and production serving infrastructure
• Strong understanding of ML experiment design, including training data validity, label quality, recall/precision tradeoffs under constrained thresholds, and causal inference fundamentals

Benefits

• Annual Salary Range: $196,750—$243,290 USD
• Equity compensation
• Benefits as described on this page