Senior Data & Machine Learning Engineer

ABOUT THE ROLE Join a small, early-stage AI team building a recommendation system for personalized advertising. You will own the matching stack end to end, from data and models through real-time serving, and help shape the system's technical priorities as it scales. WHAT YOU'LL DO - Build retrieval, ranking, and re-ranking systems to match ads with recipients. - Develop embedding and vector-search infrastructure for real-time ad selection. - Optimize ranking across click-through rate, advertiser return, publisher revenue, and subscriber relevance. - Own the feature store, offline training, online inference, serving path, and pipeline health. - Apply large language models and foundation models to subscriber tagging, content understanding, and user modeling. - Take initiatives from prototype to production, including online learning, feedback loops, ETL/ELT pipelines, and warehouse transformations. - Create dashboards and automated scorecards to track performance and key metrics. - Partner with company leadership and engineering to set priorities, with an opportunity to grow into leading an ML team. WHAT WE'RE LOOKING FOR - At least 3 years of experience with recommendation, ranking, or advertising systems, and 5 to 16 years of overall experience. - Production experience owning recommendation or matching systems across candidate generation, ranking, embedding-based retrieval, serving, and evaluation. - Experience building ad ranking, click-through or conversion prediction, or ad-matching models. - Hands-on experience with embeddings and real-time vector search tools such as FAISS, Milvus, Pinecone, pgvector, or similar. - Strong SQL skills and experience building data pipelines and transformation layers with dbt or similar tools, plus Postgres or columnar analytical databases. - Early-stage startup or founder experience is valued; experience building an ML team and graduate study in computer science or machine learning are also relevant. COMPENSATION & BENEFITS Base salary: $200,000 to $300,000 annually. Visa sponsorship is not available. LOCATION Hybrid, with preference for candidates in the New York City area or in a nearby U.S. time zone who can travel to New York City quarterly.