Sr. Machine Learning Engineer

The opportunity
Unity's Ads Experimentation Platform team is looking for a Machine Learning Engineer to lead the infrastructure and systems that power how we validate and evolve our global advertising ecosystem. Our ads reach billions of devices, and the ability to ship ML models and pipeline changes with speed and confidence is critical to our growth.In this role, you will own the technical roadmap for experimentation and evaluation at scale. You will design and build the systems that enable ML teams to iterate faster — moving beyond standard A/B testing into high-sensitivity evaluation, causal inference, and automated experimentation infrastructure. This is a high-impact engineering role at the intersection of ML systems, data infrastructure, and experimentation platform development.

What you'll be doing

• Build high-sensitivity experimentation infrastructure: Design and implement variance reduction techniques (CUPED) and sequential testing frameworks that increase platform sensitivity and accelerate decision-making. Architect solutions to handle interference and network effects in a complex auction environment.
• Architect and deploy interleaving systems: Build interleaving frameworks that evaluate ranking model performance in real time, enabling the team to identify winning candidates orders of magnitude faster than standard bucket testing.
• Engineer budget-aware evaluation systems: Develop pacing-aware methodologies and tooling that account for finite advertiser budgets and prevent experimental groups from cannibalizing each other's spend — maintaining marketplace integrity and result validity at scale.
• Build LTV proxy metric pipelines: Design and implement surrogate metric systems that correlate with long-term user retention and value, giving ML teams reliable short-term signals for long-term optimization.
• Develop automated ML experimentation pipelines: Build the infrastructure for automated systems that test and select optimal features and hyperparameters, reducing manual overhead and accelerating model deployment at scale.
• Drive technical standards across teams: Serve as the experimentation platform's lead engineer across ML, Product, and Engineering, ensuring statistical rigor is built into systems from model training through live production auctions.

What we're looking for

• 5+ years of ML engineering experience, ideally within Ad Tech, Marketplaces, or large-scale experimentation platforms
• Strong systems thinking and engineering fundamentals — you build things that run reliably in production at scale
• Proficiency in Python or Scala and hands-on experience with large-scale data processing frameworks (Spark, Snowflake, BigQuery)
• Practical experience implementing advanced testing methodologies — CUPED, interleaving, switchback testing — in production environments
• Solid understanding of causal inference and experimental design, applied through an engineering lens
• Ability to translate complex technical tradeoffs into clear roadmap decisions and influence across engineering teams

You might also have

• Experience building or maintaining internal experimentation platforms at a major tech company
• Familiarity with LTV prediction and surrogate metric design in mobile gaming or digital advertising

Additional information

• Relocation support is not available for this position
• Work visa/immigration sponsorship 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