Machine Learning Engineer, Next-Generation Recommendation Systems

Unity Technologies; Mountain View (CA); On-site; USD 127,400 - 191,200; Full time

Job summary

Unity Technologies is seeking a PhD graduate to advance next‑generation ranking and recommendation models. You will work with LLMs, RLHF, and preference learning to improve ad relevance at scale, designing experiments and collaborating with engineering to bring research into production.

You will develop conversion prediction and behavioral models, optimize bidding strategies, and communicate results across engineering, product, and business teams. Strong publication history is highly valued.

Qualifications

• PhD in CS/ML/statistics or related field; graduating 2026 or recent.
• Strong foundations in recommendation systems, RL, LLM post-training/alignment, human‑AI collaboration, probabilistic modeling, or optimization.
• Experience with large-scale data and ML systems through research or internships.
• Fluent in Python; familiar with PyTorch or TensorFlow.

Responsibilities

• Design, build, and evaluate next‑gen ranking and recommendation models with LLMs, RLHF, and preference learning.
• Develop user understanding systems: conversion prediction, behavioral modeling, and value estimation at scale.
• Apply reinforcement learning and optimization to bidding, auction dynamics, and real-time delivery.
• Design and run rigorous experiments using causal inference, A/B testing, and offline evaluation.
• Partner with engineering to deploy research ideas from data to production across the pipeline.
• Communicate findings clearly to both technical and non‑technical stakeholders.

Skills

Python programming

Large-scale ML systems

Research publications

Communication skills

Ad tech / ML in ads

Education

PhD in Computer Science / ML / Statistics

Tools

PyTorch

TensorFlow

Job description

The opportunity

Unity's Vector AI team builds the machine learning systems that decide which ads reach which players — across billions of monthly users on the world's leading game engine. Recommendation and ranking systems are the core of this work: predicting user value, optimizing bids, and delivering outcomes for advertisers at massive scale.

We are building the next generation of these systems. The frontier has shifted — large language models, reinforcement learning from human feedback, and agentic AI are reshaping what recommendation systems can do. We are looking for PhD graduates who have worked at that frontier and want to bring those ideas into production systems that matter.

What you’ll be doing

• Design, build, and evaluate next-generation ranking and recommendation models that incorporate LLMs, RLHF, and preference learning to improve ad relevance and user experience.

• Develop user understanding systems — conversion prediction, behavioral modeling, and value estimation — that operate across billions of impressions.

• Apply reinforcement learning and optimization techniques 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 to measure and improve model quality.

• Partner with engineering to bring research ideas into production, working across the full pipeline from training data to deployed model.

• Communicate findings clearly to technical and non-technical stakeholders across engineering, product, and business teams.

What we’re looking for

• PhD in Computer Science, Machine Learning, Statistics, or a related field (graduating 2026 or recent graduate).

• Strong research foundations in one or more of: 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, whether through research or industry internships.

• Fluency in Python; familiarity with ML frameworks such as PyTorch or TensorFlow.

• A track record of rigorous, high-quality research — publications at top venues (NeurIPS, ICML, ICLR, KDD, RecSys, ACL, WWW, or similar) are a strong signal.

• Strong written and verbal communication skills — able to make complex ideas accessible across technical and non-technical audiences.

You might also have

• Industry experience in ads, recommendation, or user understanding systems (internship experience counts).

• Hands-on experience with production ML pipelines — training at scale, feature engineering, or experimentation infrastructure.

• Experience applying LLMs or generative models to ranking, retrieval, or structured prediction problems.

• Familiarity with agentic AI approaches — multi-step reasoning, tool use, or human-AI collaboration frameworks.

• Exposure to causal inference, uplift modeling, or A/B testing at scale.

• Genuine curiosity about applied research and the drive to see ideas through to impact.

Additional information

• Relocation support is not available for this position

$127,400.00 - $191,200.00

This range reflects the anticipated base salary for this position. Beyond base salary, this role may be eligible for equity awards and participation in our company incentive plans (such as annual discretionary bonuses or sales commissions). The final offer amount will depend on several factors, including geographic location and the candidate’s relevant experience, professional background, and skill set.

Benefits

At Unity, we want our team members to thrive. We offer a wide range of benefits designed to support well-being and work-life balance.

Please note: Benefits eligibility, specific offerings, and coverage vary based on the country and employment status.

While specific benefits vary, here are some of the ways we strive to take care of our eligible team members globally: Comprehensive health, life, and disability insurance | Commute subsidy | Employee stock ownership | Competitive retirement/pension plans | Generous vacation and personal days | Support for new parents through leave and family-care programs | Office food snacks | Mental Health and Wellbeing programs and support | Employee Resource Groups | Global Employee Assistance Program | Training and development programs | Volunteering and donation matching program

Unity is a proud equal opportunity employer. We are committed to fostering an inclusive, innovative environment and celebrate our employees across age, race, color, ancestry, national origin, religion, disability, sex, gender identity or expression, sexual orientation, or any other protected status in accordance with applicable law. Our differences are strengths that enable us to support the growing and evolving needs of our customers, partners, and collaborators.

If you have a disability that means there are preparations or accommodations we can make to help ensure you have a comfortable and positive interview experience, please fill out this form (https://docs.google.com/forms/d/e/1FAIpQLSdrbRLG1N-apH1eahQ622Gypo-rmiAB6LLTP1UsSWQNu7omxQ/viewform) to let us know.

This position requires the incumbent to have a sufficient knowledge of English to have professional verbal and written exchanges in this language since the performance of the duties related to this position requires frequent and regular communication with colleagues and partners located worldwide and whose common language is English.

This posting is intended to fill an existing vacancy, and we are committed to providing applicants with updates throughout the hiring process in accordance with applicable law.

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