Senior Machine Learning Scientist (AI)

Location: London, United Kingdom; hybrid work with the option to work onsite as often as required by the team

Company

hirify.global, part of Tripadvisor Group, operates a global marketplace for travel experiences and helps travelers discover and plan activities.

What you will do

• Lead machine learning projects for Search, Retrieval, Ranking, and Content AI capabilities within the discovery engine.
• Design and implement custom model components and loss functions, translating research goals into iterative deliverables.
• Evaluate and adapt state-of-the-art architectures while balancing model quality, inference speed, memory usage, and execution costs.
• Optimize production models through techniques such as quantization and distillation.
• Build golden datasets, leaderboards, backtesting, slice-based evaluation, and automated checks for leakage, overfitting, regressions, concept drift, and feature shifts.
• Partner with engineering leads on compute and GPU infrastructure, model handovers, fallback systems, post-mortems, and mentoring of mid-level and associate machine learning scientists.

Requirements

• Master’s or Ph.D. degree in Computer Science, Machine Learning, Statistics, or a highly quantitative field.
• 5+ years of industry experience developing, validating, and deploying large-scale machine learning models in production environments.
• Strong practical and theoretical foundation in machine learning, feature engineering, and deep learning.
• Ability to adapt, hybridize, and tune state-of-the-art architectures for non-linear business problems.
• Mastery of Python and deep learning frameworks such as PyTorch, PyTorch Lightning, or TensorFlow.
• Familiarity with data versioning and experiment tracking tools.

Nice to have

• Experience with multi-task learning, ranking, Content AI, or Agentic AI.
• Experience with next-generation retrieval pipelines, multi-stage ranking systems, and Content AI stacks.
• Advanced sequential recommendation systems modeling real-time user session dynamics.
• Graph Neural Networks, knowledge graphs, and multi-modal representation learning for travel entities.
• Generative AI and Agentic AI workflows for conversational discovery.

Culture & Benefits

• Remote-friendly collaboration across a worldwide team, with flexible onsite participation based on lifestyle and team requirements.
• Flexible scheduling designed to support work-life balance.
• Competitive compensation including base salary and annual bonuses.
• Health benefits, employee assistance programs, donation matching, tuition assistance, lifestyle benefits, and travel perks.
• Traveler-first, execution-focused, collaborative, inclusive, and data-driven working culture.