Senior Machine Learning Scientist (Search Marketing & Tech)

Location: London, United Kingdom

Company

hirify.global is a global travel company operating consumer brands, a B2B travel network, and travel advertising businesses.

What you will do

• Own end-to-end machine learning solutions from problem framing and metric design through deployment and post-launch iteration.
• Define model architectures, system designs, data contracts, and integration patterns.
• Lead multi-quarter ML initiatives with engineering, product, and business stakeholders.
• Design production-grade models for metasearch bidding and auction strategies across Google Hotel Ads, Trivago, and Tripadvisor.
• Build training, evaluation, serving, observability, drift detection, and failure-handling pipelines.
• Mentor data and machine learning scientists and drive adoption of AI best practices.

Requirements

• Master’s or PhD in Computer Science, Statistics, Applied Mathematics, Operations Research, or a related quantitative field, or equivalent industry experience.
• 6+ years of hands-on machine learning experience with a Master’s degree or 4+ years with a PhD.
• Experience leading a complex, multi-stakeholder production ML initiative with measurable business impact.
• Deep knowledge of supervised and unsupervised learning, experimentation, statistics, causal inference, and model evaluation.
• Fluency in Python and machine learning libraries including pandas, NumPy, scikit-learn, PyTorch, or TensorFlow.
• Strong SQL skills and experience with large-scale data processing technologies such as Spark or Hive.

Nice to have

• Experience with advertising, auctions, marketplace optimization, bidding systems, or ROI optimization.
• Knowledge of constrained optimization, reinforcement learning, or bandit methods.
• Experience with feature stores, model registries, CI/CD for ML, monitoring, and alerting.
• Exposure to large language models, foundation model fine-tuning, or AI/ML-driven systems.

Culture & Benefits

• Work supporting travel products used by millions of customers.
• Collaborative environment spanning engineering, product, business, and data science.
• Flexible benefits and support for professional growth.
• Inclusive and accessible recruiting experience with accommodation support available.