Principal Machine Learning Scientist (AI)

Location: London, United Kingdom; hybrid and remote-friendly collaboration with on-site attendance as required by the team

Company

hirify.global connects travelers with experiences, travel guidance, and two-sided marketplaces across accommodations, restaurants, tours, and other travel categories.

What you will do

• Lead the technical roadmap for search, retrieval, ranking, and recommendation systems within the Trips vertical.
• Design, prototype, and scale multi-task, sequential, and representation-learning models for travel discovery.
• Oversee low-latency, high-throughput retrieval and ranking pipelines, including multi-stage retrieval and vector search.
• Translate business objectives into scalable production ML architectures supporting engagement and booking conversion.
• Collaborate with product managers, engineering leads, and data science peers as the primary technical authority for ML initiatives.
• Mentor senior and mid-level ML scientists and establish practices for MLOps, A/B testing, privacy, and code quality.

Requirements

• Ph.D. or Master’s degree in computer science, machine learning, statistics, or a highly quantitative field.
• 8+ years of industry experience developing and deploying large-scale ML models in production for millions of active users.
• Strong expertise in multi-task learning, MMoE or similar architectures, sequential recommendation, temporal modeling, and multi-modal representation learning.
• Mastery of Python and deep learning frameworks including TensorFlow and PyTorch.
• Hands-on experience with distributed computing using Spark or Ray and cloud infrastructure such as AWS or GCP.
• Ability to work in the London, United Kingdom hybrid setup, including on-site attendance as required by the team.

Nice to have

• Experience with graph neural networks, knowledge graphs, or graph embeddings.
• Familiarity with agentic AI, LLM-driven reasoning, or autonomous planning agents.
• Experience in e-commerce, travel technology, or two-sided marketplaces with constrained inventory.
• Academic or industry contributions to top-tier AI or information-retrieval conferences, or open-source ML projects.

Culture & Benefits

• Flexible schedule with a focus on work-life balance, trust, and accountability.
• Remote-friendly collaboration and the option to work on-site according to team needs.
• Competitive compensation with base salary and annual bonuses.
• Health benefits, employee assistance programs, tuition assistance, lifestyle benefits, travel perks, and donation matching.
• Inclusive and accessible candidate experience with reasonable accommodation support.