Senior Machine Learning Engineer, Ads Fraud Detection

The opportunity

Our Foundation Modeling team plays a central role in this effort by developing state-of-the-art conversion rate (CVR) prediction, market price models, and fraud detection systems that identify and block fraudulent activities at the publisher, game, and user levels.

These models power our ad ranking and recommendation systems, helping 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 lead the development of advanced fraud detection solutions, driving system performance, scalability, and robustness to ensure Unity Ads remains a secure and reliable platform for all stakeholders.

What you'll be doing

• Design, implement, and maintain high-performance fraud detection models to identify and block fraudulent activities at the publisher, game, and user levels.
• Build and refine systems to analyze user behavior, transaction patterns, and contextual signals, enabling accurate and timely detection of suspicious or malicious activity.
• 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 systems for detection, monitoring, or risk management in ads, payments, or related domains.
• 3+ years of experience designing and deploying fraud detection or anomaly detection models, user behavior modeling, or risk scoring 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.

Life at Unity

Unity [NYSE: U] is the leading platform to create and grow games and interactive experiences. Creators, ranging from game developers to artists, architects, automotive designers, infrastructure experts, filmmakers, and more, use Unity to bring their imaginations to life across multiple platforms, from mobile, PC, and console, to spatial computing.

As of the third quarter of 2024, more than 70% of the top 1,000 mobile games were made with Unity, and in 2024, Made with Unity applications had an average of 3.7 billion downloads per month. For more information, please visit Unity.

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 to let us know.

Pursuant to the San Francisco Fair Chance Ordinance, we will consider for employment qualified applicants with arrest and conviction records.

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.

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*Note: Certain locations require a good faith disclosure of the base salary range for the role. The actual salary for the successful candidate may differ based on location, experience, and other job-related factors.