Principal Machine Learning Scientist - Search and Personalization

11105 Expedia, Inc.; United States; On-site; USD 224,000 - 314,000; Full time

Benefits offered by this job

Medical, dental & vision coverage

Paid time off

Employee Assistance Program

Wellness & travel reimbursement

Travel discounts

IATAN membership

Job summary

Expedia Group is seeking a Principal Applied Scientist to join our Personalization, Search & Recs team. You will lead research and production-ready ML solutions for large-scale travel search and recommendations, combining multi-modal data and context-aware personalization.

The role requires 10+ years in ML, strong Python and ML framework skills, and experience deploying production systems. Collaboration across teams and mentoring is essential in a fast-paced, AI-driven travel platform.

Qualifications

• PhD or MS in Computer Science, ML, Statistics, Engineering or related field, or equivalent experience.
• 10+ years of industry experience in ML, AI, or related field.
• Experience building production-grade search, recommendation or personalization systems.

Responsibilities

• Drive research, design, and deployment of ML solutions for large-scale search/recommendations.
• Architect hybrid multi-modal retrieval frameworks with text, image, and data.
• Develop multi-stage ranking pipelines using deep learning and generative methods.
• Lead intent understanding using user queries and behavior signals.
• Advance personalization with embeddings and context-aware algorithms.
• Pioneer sequential recommender systems accounting for user dynamics.
• Design offline/online evaluation methods including A/B testing.
• Collaborate with cross-functional teams to translate business needs into ML products.
• Mentor and guide a team of scientists and engineers.

Skills

PhD or MS

10+ years experience

Python

TensorFlow/JAX/PyTorch

Spark

Hadoop

Cloud platforms (AWS/GCP/Azure)

A/B testing

Bias & fairness

Communication

Mentoring

Travel/e‑commerce domain

Education

PhD or MS in CS/ML/Statistics/Engineering

Tools

Spark

Hadoop

AWS

GCP

Azure

TensorFlow/PyTorch/JAX

Job description

Introduction to the Team

At Expedia Group, we help travelers explore the world, one journey at a time. As a global travel company powered by passionate people, trusted partnerships, and leading technology, we connect travelers, partners, and advertisers through our consumer brands, B2B network, and travel advertising business. Here, you'll do meaningful work that helps millions of people discover, book, and experience travel with more ease, confidence, and joy. Our five Behaviors-Traveler First, Think Big, Operate with Excellence, Ownership Mindset, and Succeed Together-help foster a supportive environment where people can grow their careers and have the flexibility, benefits, and support to do their best work. Join us and build for travelers everywhere.

Team Overview

Introduction to the Team Expedia Technology teams partner with our Product teams to create innovative products, services, and tools to deliver high-quality experiences for travelers, partners, and our employees. A singular technology platform powered by data and machine learning provides secure, differentiated, and personalized experiences that drive loyalty and traveler satisfaction. We are looking for a Principal Applied Scientist to join our growing Personalization, Search & Recs team. This Principal will be a key contributor to thought leadership, development and optimization of Expedia’s Search & Personalization AI models including natural language search, multi-modal search, recommendations, and generative AI–based traveler experiences. The ideal candidate for this position is a true deep learning, ML expert who can develop effective AI solutions for search and recommendations. Innovation and developing cutting‑edge technology as well as implementing industry‑leading solutions are key responsibilities of this role. This is a rare opportunity to build foundational systems in a high‑impact strategic area, backed by Expedia’s AI‑first vision.

In this role, you will:

• Drive the research, design, and deployment of advanced machine learning solutions for large-scale search and recommendation systems
• Architect hybrid multi-modal retrieval frameworks, combining text, image, and structured data to power relevant and diverse content discovery
• Develop and optimize multi‑stage ranking pipelines, leveraging deep learning, generative retrieval, and other advanced algorithms to maximize relevance and engagement
• Lead efforts on intent understanding, utilizing user queries, behavioral signals, and context for superior search and recommendation accuracy
• Advance personalization strategies using embeddings, user‑item modeling, and context‑aware algorithms to tailor content to individual users
• Pioneer cutting‑edge sequential recommender systems that account for evolving user preferences, session context, and temporal dynamics
• Design robust offline and online evaluation methodologies, including A/B testing, counterfactual estimation, and metric development
• Collaborate closely with cross‑functional engineering and product teams to translate business needs into machine learning problems and production‑ready solutions
• Mentor and guide a team of scientists, driving best‑in‑class research and deployment practices

Minimum Qualifications

• PhD, or MS, in Computer Science, Machine Learning, Statistics, Engineering, or a related field; or equivalent professional experience
• 10+ years of related industry experience
• Experience building production‑grade search, recommendation or personalization systems
• Strong understanding of intent understanding techniques, retrieval methods, deep learning for recommendations, reinforcement learning, and causal inference
• Proficiency in Python and ML frameworks such as TensorFlow, JAX, or PyTorch
• Experience with large‑scale distributed systems and big data technologies (e.g., Spark, Hadoop)
• Familiarity with A/B testing and experimentation methodologies
• Ability to work with large-scale, real‑world data with attention to bias, fairness, and privacy
• Excellent communication skills for both technical and non‑technical audiences
• Demonstrated ability to mentor and technically lead research or engineering teams
• A passion for building user‑centric AI products and a keen curiosity about advancing the state‑of‑the‑art in search and recommendations

Preferred Qualifications

• Experience in the travel or e‑commerce industry
• Familiarity with cloud platforms (AWS, GCP, Azure)
• Publications in top‑tier ML conferences or journals
• Contributions to open‑source ML projects
• Experience in personalization systems
• Experience taking models from prototype to production in collaboration with Machine Learning Engineering teams

Salary & Payment

The total cash range for this position in Seattle is $224,000.00 to $313,500.00. Employees in this role have the potential to increase their pay up to $358,500.00, which is the top of the range, based on ongoing, demonstrated, and sustained performance in the role. The total cash range for this position in SanJose is $242,000.00 to $338,500.00. Employees in this role have the potential to increase their pay up to $387,000.00, which is the top of the range, based on ongoing, demonstrated, and sustained performance in the role. Starting pay for this role will vary based on multiple factors, including location, available budget, and an individual’s knowledge, skills, and experience. Pay ranges may be modified in the future.

Benefits and perks

Expedia Group offers benefits and perks designed to support employees and their families, including medical, dental, and vision coverage, paid time off, an Employee Assistance Program, wellness and travel reimbursement, travel discounts, and International Airlines Travel Agent Network (IATAN) membership.

Accommodation requests

Expedia Group is committed to providing an inclusive and accessible recruiting experience. If you need an accommodation or adjustment due to a disability during the application or recruiting process, please submit a request at https://expedia.service-now.com/askeg?id=job_accommodation.

About Expedia Group

Expedia Group includes three flagship consumer brands – Expedia, Hotels.com, and Vrbo – along with a leading B2B travel business and travel advertising offerings. Across our brands and business, we help travelers explore the world with confidence and ease.

Expedia Group™ connects travelers, partners, and advertisers through its trusted brands, leading technology, and rich first‑party data, delivering predictive, personalized experiences that shape the future of travel. Expedia Group’s ecosystem includes three flagship consumer brands – Expedia®, Hotels.com®, and Vrbo® – the largest B2B travel business, and a premier advertising network. Guided by an experienced and passionate global team, Expedia Group helps millions of travelers in more than 70 countries explore the world with confidence and ease.

Equal Opportunity

Equal Opportunity 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. The employer will provide the Social Security Administration (SSA) and, if necessary, the Department of Homeland Security (DHS) with information from each new employee’s I‑9 to confirm work authorization.