ML Engineer — Next-Gen Recommendations with LLMs & RLHF

Unity; Mountain View (CA); On-site; USD 150,000 - 230,000; Full time

Benefits offered by this job

Health insurance

Stock ownership

Generous vacation

Office snacks

Employee Resource Groups

Training programs

Commute subsidy

Retirement plan

Parental leave

Mental health support

EAP

Volunteering match

Job summary

Unity is seeking PhD graduates to join the Vector AI team to design, build, and evaluate next-generation ranking and recommendation models that incorporate LLMs, RLHF, and preference learning to improve ad relevance and user experience.

You will develop user understanding systems—conversion prediction and behavioral modeling—operating across billions of impressions, and apply reinforcement learning to bidding strategy and real-time ad delivery, collaborating with engineering and product teams.

Qualifications

• Fluency in Python; familiarity with ML frameworks such as PyTorch or TensorFlow
• Strong written and verbal communication skills
• PhD in Computer Science, Machine Learning, Statistics, or related field (graduating 2026 or recent graduate)
• Strong research foundations in one or more: recommendation systems, reinforcement learning, LLM post-training or alignment, human-AI collaboration, probabilistic modeling, or optimization
• Experience working with large-scale data and ML systems
• A track record of rigorous research — top venue publications
• Industry experience in ads, recommendation, or user understanding systems
• Hands-on experience with production ML pipelines
• Experience applying LLMs or generative models to ranking, retrieval, or structured prediction
• Familiarity with agentic AI approaches
• Exposure to causal inference, uplift modeling, or A/B testing

Responsibilities

• Design, build, and evaluate next-generation ranking and recommendation models that incorporate LLMs, RLHF, and preference learning
• Develop user understanding systems — conversion prediction and behavioral modeling across billions of impressions
• Apply reinforcement learning to bidding strategy, auction dynamics, and real-time ad delivery
• Design and run rigorous experiments using causal inference, A/B testing, and offline evaluation frameworks
• Partner with engineering to bring research ideas into production across training data to deployed models
• Communicate findings clearly to technical and non-technical stakeholders across teams

Skills

Python

ML frameworks

Communication

PhD in CS/ML/Stats

Reinforcement learning

Recommendation systems

LLMs/RLHF

Large-scale data

Production ML pipelines

A/B testing / causal inference

Education

PhD in Computer Science, Machine Learning, Statistics, or related field

Job description

Unity is seeking PhD graduates to join the Vector AI team to design, build, and evaluate next-generation ranking and recommendation models that incorporate LLMs, RLHF, and preference learning to improve ad relevance and user experience.

You will develop user understanding systems—conversion prediction and behavioral modeling—operating across billions of impressions, and apply reinforcement learning to bidding strategy and real-time ad delivery, collaborating with engineering and product teams.