Principal Machine Learning Engineer (Matchmaking)

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

Salary: $295,250–$345,040 USD annual base pay, with equity compensation and benefits eligibility.

Company

Roblox builds a platform and tools for creating and participating in 3D immersive digital experiences.

What you will do

• Own the technical direction and ML strategy for matchmaking connecting Discovery and Search to server placements.
• Define objective functions balancing player and developer utility with latency, engagement, retention, server utilization, reliability, and compute cost.
• Build predictive models for player–server outcomes using player history, game characteristics, and live server state.
• Design and productionize candidate-server retrieval, ranking, and assignment algorithms under real-time latency, capacity, and reliability constraints.
• Build data, feature, training, serving, and evaluation systems with fresh signals and training-serving consistency.
• Lead through technical direction and mentorship, partner with product and infrastructure teams, and run offline evaluations and online experiments.

Requirements

• 8+ years of experience delivering and improving large-scale ML systems for ranking, recommendation, personalization, or resource allocation.
• Experience defining objective functions, building predictive models, and deploying optimization algorithms under production latency, reliability, and resource constraints.
• Ability to break long-term product requirements into iterative deliverable stages and facilitate difficult technical decisions across multiple teams and organizations.
• Deep technical expertise focused on user needs, with a generalist approach and mastery of several languages and technologies.
• Ability to address data and machine learning problems directly, simplify complex problems, and develop creative and strategic solutions.
• BS in Computer Science or a related discipline.

Nice to have

• MS or PhD in Computer Science or a related discipline.

Culture & Benefits

• Full-time employees are eligible for equity compensation and benefits.
• Work is conducted onsite Tuesday through Thursday for office-based roles, with optional presence on Monday and Friday.
• Equal employment opportunities and reasonable accommodations are provided during the recruiting process.