Senior Machine Learning Engineer, Conversion Modeling

The opportunity

We are looking for a Staff Machine Learning Engineer to join our Vector Core Modeling team. In this role, you will design and build scalable machine learning systems that power ad ranking in large-scale advertising platforms.

As a key member of the Vector AI group, you will play a central role in driving Unity’s ads engine. You will work with massive datasets and rich signals to develop the state-of-the-art ads models. These models serve as the core intelligence behind delivering the right ad to the right user at the right time, maximizing both user experience and advertiser outcomes.

What you'll be doing

• Design, implement, and optimize the core ads models
• Build and enhance multi-objective ranking systems balancing retention, monetization, diversity, and user long-term value
• Solve cold-start problems for new users, new games, and new creatives
• Conduct offline evaluations and online A/B experiments to deliver measurable impact
• Partner closely with product, infrastructure, and monetization teams
• Continuously improve model quality, serving latency, and system scalability

What we're looking for

• Hands-on experience applying state-of-the-art machine learning and deep learning models to complex real-world problems
• Strong software engineering skills in Python and experience with deep learning frameworks, preferably PyTorch
• Solid understanding of metric design, experimentation frameworks, and large-scale data analysis
• Proven ability to lead projects end-to-end and deliver measurable business impact

You might also have

• Experience working with large datasets and distributed computing frameworks
• Experience building ads systems, content understanding, or behavior modeling systems
• Experience embracing AI as a strategic advantage in engineering, following established best practices for code quality and security

Additional information

• International relocation support is not available for this position

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

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.

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.

Headhunters and recruitment agencies may not submit resumes/CVs through this Web site 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.

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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.