Machine Learning Engineer II, Marketing Testing

We are seeking a Machine Learning Engineer to work on two key areas within our marketing analytics team. First, you'll enhance our production experimentation platform that runs large-scale tests, helping marketers design, launch, and evaluate experiments efficiently and reliably. Second, you'll help build new flexible measurement tools by creating open-source style add-ons and turning research prototypes into production-ready solutions. This includes developing reusable code libraries for quick analysis and designing tools that work alongside our existing platform. If you're passionate about building scalable ML systems that drive business impact and enjoy turning innovative prototypes into robust production tools, this could be the perfect role for you! You'll play a key role in maintaining our current experimentation platform while helping to build the next generation of marketing measurement tools. In this role, you will:

Support software engineering teams to maintain platform performance, troubleshoot issues, and enhance logging systems to ensure reliable operation for 300+ annual experiments Optimize core testing code including stratified sampling, simulation and regression frameworks Build scalable data pipelines for experiment execution and analysis Build flexible measurement tools, create reusable code libraries, and transform research prototypes into production-ready solutions Collaborate with data scientists and software engineers to translate requirements and coordinate deployment of tools into production

Bachelor's or Master's degree in Computer Science, Engineering, Mathematics, or related technical field; or equivalent professional experience Proficient in Python, SQL, and PySpark for large-scale data processing Experience building scalable systems, preferably with ML/AI components in production environments Experience with automated testing and deployment practices, including version control, unit testing, and deployment pipelines (e.g. GitHub Actions) Understanding of system internals, including memory management, caching, and distributed computing Experience turning prototypes into production code and building flexible, reusable code frameworks Foundational knowledge in machine learning principles and statistical methods

Desirable:

Familiarity with cloud platforms (AWS, GCP) Familiarity with open-source development practices and creating modular, adaptable tools Knowledge of A/B testing methodologies, stratified sampling, and experimental design principles

Expedia Group brands power global travel for everyone, everywhere. We design cutting-edge tech to make travel smoother and more memorable, and we create groundbreaking solutions for our partners. Our diverse, vibrant, and welcoming community is essential in driving our success. Why Join Us? To shape the future of travel, people must come first. Guided by our Values and Leadership Agreements, we foster an open culture where everyone belongs, differences are celebrated and know that when one of us wins, we all win. We provide a full benefits package, including exciting travel perks, generous time-off, parental leave, a flexible work model (with some pretty cool offices), and career development resources, all to fuel our employees' passion for travel and ensure a rewarding career journey. We're building a more open world. Join us. Machine Learning Engineer II, Marketing Testing Introduction to team The Traveler Business Team builds and drives growth for our global consumer businesses-Expedia, Hotels.com, and Vrbo. This division creates compelling and differentiated traveler value for each brand by setting the strategic vision, operating strategy, and plan. Responsibilities include investment allocation and prioritization, P&L accountability, and leading cross-functional teams across Expedia Group, who are all held accountable to a single scorecard. Within this division, our Marketing Measurement Analytics team is dedicated to driving data-informed marketing decisions across Expedia Group's portfolio of brands. We build sophisticated measurement capabilities and experimentation platforms that enable marketers to optimize their strategies and demonstrate clear business impact.