Machine Learning Scientist III - Personalization

About the Role

We are looking for a Machine Learning Scientist III to help build production‐level ML systems for Expedia’s Unified Personalization Service (UPS). The role focuses on deep learning, neural recommender systems, sequential and session‑based modeling, embeddings, scalable experimentation, and reliable model deployment. It is a hands‑on applied science and engineering role that spans model development, experimentation, data pipelines, deployment, and production model quality.

• Develop, apply, and advance machine learning solutions for personalization use cases, translating business and customer problems into scalable scientific approaches and production‑ready models.
• Design experiments, evaluate model performance, and use data‑driven methods to improve relevance, ranking, recommendation, and overall customer experience across personalization systems.
• Partner across engineering, product, analytics, and science teams to define solution approaches, influence technical direction, and deliver ML capabilities that can operate across multiple products and domains.
• Contribute technical depth in model development, feature design, data preparation, offline and online evaluation, and the operationalization of machine learning solutions in production environments.
• Apply strong technical judgment to system design, API design, data modeling, and low‑level solution design that support robust, maintainable, and extensible ML‑powered services.
• Safely integrate and operate AI/ML‑enabled solutions that improve outcomes, including familiarity with AI‑driven systems, tools, or workflows and applying AI/ML concepts to real world products.

• Bachelor’s degree in Computer Science, Machine Learning, Statistics, Mathematics, or a related technical field, or equivalent professional experience.
• 5+ years of relevant experience in machine learning, applied science, data science, or software development, including delivering production‑grade ML solutions.
• Demonstrated ownership of machine learning solutions within a service, multi‑service, or domain‑level scope, with accountability for model quality, experimentation, and operational performance.
• Strong foundation in machine learning methods, statistical analysis, experimentation, feature engineering, and working with large‑scale datasets in production environments.
• Proficiency in software engineering practices for scientific systems, including coding, low‑level design, API design, data modeling, and collaboration with engineering teams to product ionize solutions.

• Advanced degree in Machine Learning, Computer Science, Statistics, Mathematics, or a related technical field.
• Experience building and scaling personalization, recommendation, ranking, retrieval, or relevance models in large, complex consumer‑facing environments.
• Experience with neural recommendation systems, sequential or session‑based recommendation, transformer‑based recommenders, semantic retrieval, or representation learning at scale.
• Experience with foundation models, LLMs, embedding models, semantic IDs, hybrid LLM‑recommender systems, or retrieval‑augmented personalization workflows.
• Demonstrated ability to use data, metrics, and experimentation to guide prioritization and decision‑making while balancing scientific rigor, product impact, and platform scalability.
• Experience with production ML workflows such as model serving, experimentation frameworks, feature or data pipelines, monitoring, model lifecycle management, or MLOps.

Total cash range: $149,000 – $208,500 (San Jose, CA). Potential to increase up to $238,500 based on performance. Benefits include medical/dental/vision, paid time off, wellness and travel reimbursement, travel discounts, and an International Airlines Travel Agent membership.

Expedia is committed to creating an inclusive work environment with a diverse workforce. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, veteran status, or any other characteristic protected by law. This employer participates in E‑Verify.