Machine Learning Engineer

Machine Learning Engineer III – Advertising Tech

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, flexible work, and leading career development—to fuel your passion for travel and support your career journey. We’re building a more open world. Join us.

About the Role:

Our Advertising Engineering team powers the decisioning, delivery, and personalisation of billions of ad impressions each year across Expedia Group’s 200+ global brands. As a Machine Learning Engineer III, you will harness terabytes of traveler, campaign, and context data to build ML systems for:

• Real-time ad selection, dynamic creative optimisation, and campaign effectiveness
• User targeting and bidding (e.g. bid optimisation, click/conversion prediction, contextual relevance)
• Personalisation at global scale, with a measurable impact on advertisers and travelers alike

Who Should Apply?

If you have hands-on experience building ML models and pipelines in advertising technology environments, such as with a Demand-Side Platform (DSP), Supply-Side Platform (SSP), Ad Exchange, ad server, or a large digital consumer platform’s advertising team—this is a chance to drive innovation and business impact at the heart of Expedia’s global advertising business. You’ll work shoulder-to-shoulder with scientists and engineers from ad tech giants, owning production systems with reach and complexity on par with the world’s leading AdTech firms.

What You Will Do:

• Design and scale ML pipelines for programmatic ad selection, campaign performance, and audience segmentation
• Deploy Spark-based, distributed, and real-time data flows for bidding, targeting and ad performance optimisation
• Partner with Ads Data Scientists and Software Engineers to bring models from experimentation into global production (AWS, Kubernetes, Databricks)
• Deliver advanced ML APIs and services, enabling ad delivery, targeting, and creative personalisation across Expedia Group
• Apply best practices in MLOps, model reliability, explainability and monitoring for high-stakes, high-scale ad delivery
• Mentor junior engineers and lead architectural discussions
• Continuously explore, recommend, and implement new ML methods and AdTech approaches

Required Experience:

• 5+ years as a Machine Learning Engineer, Data Scientist, or Applied Scientist, with 2+ years in advertising/ad tech
• Deep expertise in Python and either Scala or Java; strong Spark/distributed computing background
• ML production experience (PyTorch, TensorFlow), specifically for AdTech (e.g., CTR/CVR prediction, ranking, targeting, bidding, or user modelling)
• Cloud-native workflows (AWS, EMR, Databricks, SageMaker, Kubernetes); orchestration tools (Airflow, etc.)
• Experience integrating ML with business-critical ad systems and optimising for campaign/ad KPIs

Preferred:

• Experience with real-time ad systems (streaming, low-latency models)
• Prior work at Ad Platforms (DSP/SSP/Exchange/Network) or digital teams building ad personalisation, targeting, or optimisation
• Travel, e-commerce, or publisher/platform ad tech experience
• Hands-on with large-scale GPU/distributed training