Senior Machine Learning Engineer, Ads Foundation Modeling

The opportunity

At Unity, we’re committed to building a culture that fosters collaboration and innovation. Within our fast-paced environment, we’re tackling complex challenges that drive meaningful impact for creators and users across our ecosystem.

Our Foundation Modeling team plays a central role in this effort by developing state-of-the-art conversion rate (CVR) prediction and market price models that power our ad ranking and recommendation systems. These models help advertisers reach the right users at the right time by accurately estimating engagement and conversion likelihood. By leveraging large-scale behavioral data, creative features, and contextual signals, we continuously improve the relevance and accuracy of our predictions. This drives key outcomes such as higher user engagement, stronger conversion performance, and better return on ad spend — enabling advertisers to achieve their goals while delivering a better experience for users.

We are seeking a highly skilled Senior ML Engineer to drive state-of-the-art bidding optimization systems that enable efficient budget pacing, goal-aligned automated strategies, continual improvement through experimentation, and sustainable growth for Unity Ads.

What you'll be doing

• Design, implement, and maintain high-performance CTR and CVR prediction models that power ad ranking and recommendation systems.
• Build and refine systems for creative understanding and user behavior modeling, enabling more accurate and context-aware engagement predictions.
• Ensure model quality and reliability by continuously monitoring performance, calibrating predictions, and addressing data drift or delayed feedback.
• Actively participate and work with other leads to set the long term direction for the team, plan and oversee engineering designs and project execution.
• Effectively communicate complex technical concepts to non-engineering stakeholders.

What we're looking for

• Advanced degree (MS or Ph.D.) in Computer Science, Machine Learning, Statistics, related field, or equivalent practical experience.
• 5+ years of hands-on experience building and operating large-scale Ads delivery and optimization systems.
• 3+ years of experience building CTR/CVR systems, content understanding, or behavior modeling systems.
• Significant experience in one or more general-purpose programming languages like Python, Go, Scala, C++ or similar.
• Knowledge of metric design, experimentation methodologies, and large-scale data analysis.

You might also have

• Experience designing and productionizing optimization algorithms in an ad serving platform and/or other marketplaces.
• Experience with state-of-the-art control systems, reinforcement learning algorithms.

Additional information

• International relocation support is not available for this position.