Machine Learning Scientist III - Rankings & Personalization

Traveltechessentialist; City Of London; On-site; GBP 70,000 - 90,000; Full time

Job summary

A technology-driven travel company in London is seeking a Machine Learning Scientist III to innovate large-scale ranking and personalization solutions. The ideal candidate will have a PhD, significant experience in machine learning, and proficiency in Python. The role includes research and model implementation using advanced ML techniques. This position offers a full range of benefits, a flexible work model, and a dynamic work culture.

Benefits

Exciting travel perks

Generous time-off

Career development resources

Qualifications

• 2+ years of applied Machine Learning experience with end-to-end model lifecycle.
• Strong foundation in ML, statistics, ranking algorithms, and online experimentation.
• High proficiency in Python and at least one major ML framework.

Responsibilities

• Research, design, and implement advanced ML and GenAI models for ranking and personalization.
• Build, test, deploy, and iterate on ML models in production.
• Collaborate cross-functionally with engineers, data analysts, and product partners.

Skills

Machine Learning

Python

Deep Learning

Collaboration

Education

PhD in Computer Science, Engineering, Statistics, Math, or related

Tools

PyTorch

TensorFlow

Spark

Job description

Machine Learning Scientist III - Rankings & Personalization

United Kingdom - London
Technology
Full-Time Regular
11/10/2025
ID # R-97819

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 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.

The Search AI team, part of Expedia Product & Technology, powers the search and ranking experience for millions of travelers worldwide. We are seeking a Machine Learning Scientist III to shape the next generation of ranking and personalization, leveraging the latest in Large Language Models (LLMs), generative AI, and proven ML techniques.

In this role, you will:

• Research, design, and implement advanced ML and GenAI models for large‑scale ranking and personalization.
• Build, test, deploy, and iterate on ML models in production with measurable impact, validated by robust experimentation (A/B tests and online metrics).
• Combine state‑of‑the‑art ML (deep learning, representation learning) with proven approaches (learning to rank, collaborative filtering).
• Collaborate cross‑functionally with engineers, data analysts, and product partners to deliver robust, scalable, and impactful solutions.
• Stay abreast of advances in ML, GenAI, and academic research to infuse innovation.

Technologies and tools you will use and own:

• PyTorch & TensorFlow: for large‑scale development and training of deep learning models.
• Spark/Distributed Systems: for large data processing and model training at scale.
• A/B Experimentation Platforms: design, monitor, and analyze online experiments.
• Cloud ML Pipelines and Tools: to efficiently deploy, monitor, and iterate on models in production.

Minimum Qualifications:

• PhD in Computer Science, Engineering, Statistics, Math, or related.
• 2+ years of applied Machine Learning experience with end‑to‑end model lifecycle.
• High proficiency in Python and at least one major ML framework (PyTorch, TensorFlow).
• Strong foundation in ML, statistics, ranking algorithms, and online experimentation.

Preferred Qualifications:

• Experience with ranking/recommender systems at scale.
• Deep understanding of recent LLM and generative AI architectures with experience fine‑tuning and deploying them.
• Experience processing large‑scale data via distributed systems (Spark, Hadoop, etc.).
• Excellent communication and collaboration across engineering, analytics, and product teams.
• Track record of impact through production ML systems and/or peer‑reviewed publications.

Accommodation requests

If you need assistance with any part of the application or recruiting process due to a disability, or other physical or mental health conditions, please reach out to our Recruiting Accommodations Team through the Accommodation Request.

We are proud to be named as a Best Place to Work on Glassdoor in 2024 and to be recognized for award‑winning culture by organizations like Forbes, TIME, Disability:IN, and others.

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, religion, gender, sexual orientation, national origin, disability or age.