Machine Learning Engineer II, Marketing Testing

PowerToFly; Greater London; On-site; GBP 60,000 - 80,000; Full time

Job summary

A leading technology company based in the UK is seeking a Machine Learning Engineer II to enhance its marketing analytics capabilities. In this role, you will optimize core testing code and build scalable data pipelines, ensuring efficient operation for numerous experiments. The ideal candidate will have a Bachelor's or Master's degree in a technical field, proficiency in Python and SQL, and a background in ML systems. Joining our team means contributing to a dynamic work environment with excellent benefits and career development opportunities.

Benefits

Generous time-off

Parental leave

Flexible work model

Career development resources

Qualifications

• Bachelor’s or Master’s in a relevant technical field or equivalent experience.
• Experience with building scalable ML systems in production environments.
• Understanding of system internals including memory management and distributed computing.

Responsibilities

• Support software engineering teams to maintain platform performance.
• Optimize core testing code for high reliability and efficiency.
• Build scalable data pipelines for experiment execution.

Skills

Proficient in Python

SQL

PySpark

Automated testing

Deployment practices

Education

Bachelor’s or Master’s degree in Computer Science, Engineering, Mathematics

Tools

GitHub Actions

AWS

GCP

Job description

Machine Learning Engineer II, Marketing Testing

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 to 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.

About the Role

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

Experience and qualifications

Required:

• 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

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.

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.