ML Engineer, Ad Ranking with LLMs & RLHF

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

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.