Principal Applied Scientist

- Advance research and development across retrieval, ranking, matching, and generative models. - Leverage and improve SLMs/LLMs:/LRMs train, fine-tune, and align models and productionize them. - Evolve the Ads ranking platform toward better usability, reliability, scalability, efficiency, and architectural coherence. - Provide technical leadership on projects: set direction, coach a distributed team, and influence cross-org strategy. . - Follow research trends in AI to guide the group keep solutions state-of-the-art. Bachelor's Degree in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 8+ years related experience (e.g., statistics, predictive analytics, research) - OR Master's Degree in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 6+ years related experience (e.g., statistics, predictive analytics, research) - OR Doctorate in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 5+ years related experience (e.g., statistics, predictive analytics, research) - OR equivalent experience . - 8+ years of experience in ML with a proven record of shipping large-scale models to production. - Hands-on experience with SLM/LLM /LRM training, fine-tuning, and post-training. - Experience designing and scaling recommendation systems with massive query/item spaces and multi-stage ranking pipelines. - Proficiency with deep learning frameworks (e.g., PyTorch, JAX, TensorFlow) and distributed training on large datasets. These requirements include but are not limited to the following specialized security screenings: - Preferred Qualifications: - Master's Degree in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 12+ years related experience (e.g., statistics, predictive analytics, research) - OR Doctorate in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 8+ years related experience (e.g., statistics, predictive analytics, research) - OR equivalent experience. - 10+ years of experience in ML with a proven record of shipping large-scale models to production. - Proven ability to influence platform architecture and align cross-team roadmaps. - Track record of publications in tier-1 venues such as NeurIPS, ICML, KDD, WWW, ACL, SIGIR.