Senior machine learning engineer user

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. By leveraging large-scale data and contextual signals, we continuously enhance prediction relevance and accuracy. This drives outcomes such as higher user engagement, stronger conversion performance, and better return on ad spend—helping advertisers achieve their goals while delivering a more engaging experience for users.

We are seeking a highly skilled Senior ML Engineer to build and maintain advanced systems for understanding user behavior across applications. You will be responsible for improving ad ranking, conversion predictions, and recommendation systems, enabling richer behavioral models, smarter bidding strategies, and more effective ad performance.

What you'll be doing

• Design, implement, and maintain user understanding models.
• 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 in content understanding, behavior modeling, user profiling, and cohort analysis.
• 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 world’s leading game engine, powering play for more than 3 billion consumers each month. The top mobile games in the world, the most played PC indie titles, the most innovative console games, and virtually all of the top XR and Web Games are developed, deployed, and grown in Unity. Unity also enables teams across industries like automotive, manufacturing, and healthcare to design, simulate, and collaborate in 3D — closing the gap between ideas and reality. For more information, please visit

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.

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.

Headhunters and recruitment agencies may not submit resumes/CVs through this website or directly to managers. Unity does not accept unsolicited headhunter and agency resumes. Unity will not pay fees to any third-party agency or company that does not have a signed agreement with Unity. Your privacy is important to us. Please take a moment to review our Prospect and Applicant Privacy Policies. Should you have any concerns about your privacy, please contact us at [email protected].

#SEN

• 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. Gross pay salary$148,700—$223,100 USD