Senior Machine Learning Scientist (AI)

TL;DR

Senior Machine Learning Scientist (AI): Developing and deploying large-scale machine learning models for discovery engines with an accent on search, ranking, and content AI. Focus on bridging the gap between state-of-the-art research and production-grade engineering to optimize booking conversion and user engagement.

Location: London, United Kingdom (Hybrid/Remote-friendly)

Company

hirify.global is a leading global marketplace for travel experiences, part of the Tripadvisor Group, dedicated to connecting travelers with memorable tours and activities.

What you will do

• Lead technical ML projects within the discovery engine pod, designing custom model components and loss functions.
• Evaluate and deploy state-of-the-art architectures, optimizing for inference speed, memory, and cost.
• Implement rigorous validation automation, including backtesting and slice-based evaluation to ensure model reliability.
• Collaborate with Engineering Leads to define infrastructure requirements and build robust fallback systems.
• Diagnose algorithmic bugs and implement automated guardrails against concept drift and production failures.
• Mentor mid-level and associate scientists to ensure high scientific rigor and production-grade code quality.

Requirements

• Master’s or Ph.D. in Computer Science, Machine Learning, Statistics, or a highly quantitative field.
• 5+ years of industry experience developing and deploying large-scale ML models in production.
• Strong foundation in machine learning techniques, feature engineering, and deep learning paradigms.
• Mastery of Python and deep learning frameworks such as PyTorch or TensorFlow.
• Proven ability to adapt state-of-the-art architectures to solve non-linear business problems.

Nice to have

• Experience with multi-task learning, ranking systems, and Content AI stacks.
• Knowledge of Graph Neural Networks (GNNs) and multi-modal representation learning.
• Expertise in Generative AI and Agentic AI workflows for conversational discovery.
• Experience with advanced sequential recommendation systems for real-time user dynamics.

Culture & Benefits

• Competitive compensation packages including base salary and annual bonuses.
• Remote-friendly approach with flexibility to work on-site or remotely.
• Flexible schedule focused on trust, accountability, and work-life balance.
• Annual lifestyle benefit for travel or wellness and generous travel perks.
• Tuition assistance for professional development and annual donation matching.
• Comprehensive health benefits and employee assistance programs.