Senior Data Scientist - AI Search & Ranking

About the Role

Join our team as a Senior Data Scientist and play a pivotal role in enhancing how millions of travelers discover and compare hotels globally. Our Search & Ranking team supports over 35 languages and 55 countries, processing millions of queries daily. We are pioneering the next wave of AI-powered search solutions that fuse personalized ranking with advanced semantic comprehension, and we invite your expertise to help drive this evolution.

Key Responsibilities

• Design and implement scalable search and ranking systems that integrate semantic retrieval, query and intent analysis, deep learning, and Learning-to-Rank methodologies.
• Develop and deploy NLP and machine learning components enabling real-time query comprehension and personalized ranking, ensuring low latency and high system reliability.
• Fine-tune and operationalize Large Language Models (LLMs) and create AI-driven workflows for advanced query understanding, intent classification, and semantic retrieval.
• Create ranking algorithms balancing user relevance, semantic depth, and marketplace dynamics such as pricing and advertising signals to optimize user satisfaction and platform value.
• Develop robust evaluation frameworks with metrics like A/B testing, NDCG, MRR, and Precision@k to perpetually enhance search relevance and personalization.
• Employ causal inference, sequential testing, and sophisticated statistical methods to elevate search quality and user engagement.
• Collaborate closely with engineers, product managers, and fellow data scientists to deliver production-quality ML systems impacting millions worldwide.

Qualifications and Expertise

• Minimum five years’ experience in search, information retrieval, personalized ranking, NLP, machine learning, or deep learning with demonstrable product impact.
• Expert knowledge in semantic search including intent classification, Named Entity Recognition, vector-based embedding retrieval with databases such as qdrant or vespa, and Learning-to-Rank models.
• Proficiency with Large Language Models and transformer frameworks such as BERT, T5, and GPT, with skills in fine-tuning, prompt engineering, and few-shot learning tailored for search functionalities.
• Experience developing and managing production ML systems featuring real-time inference, model serving, and scalable monitoring.
• Strong programming capabilities in Python and SQL, alongside familiarity with ML frameworks including PyTorch, TensorFlow, and HuggingFace.
• Knowledge of big data platforms and cloud services like GCP and BigQuery; experience with MLOps tools such as Airflow and Kubeflow; adeptness with containerization and feature stores.
• Comprehensive statistical expertise, particularly in designing and assessing extensive A/B testing.
• Exceptional problem-solving aptitude with a proactive, entrepreneurial mindset; able to navigate uncertain environments, balance rapid prototyping with in-depth research, and tailor solutions to both short- and long-term objectives.
• Excellent communication and teamwork skills with a history of effective collaboration across functions and mentoring junior team members.
• Master's or PhD degree in NLP, Computer Science, Machine Learning, Statistics, Mathematics, or a related quantitative discipline.

Additional Advantages

• Experience in orchestrating LLM-based agentic workflows using frameworks such as LangChain and LlamaIndex for semantic search applications.
• Background in two-sided marketplace ranking systems within e-commerce, travel, or digital advertising sectors.
• Expertise optimizing AI system performance concerning latency, cost-efficiency, and output quality in production environments.