Principal Machine Learning Engineer

Responsibilities

• Apply state-of-the-art machine learning and LLM techniques to problems across personalization, query understanding, user and content understanding
• Rigorously evaluate ML and LLM models using offline analysis and online experimentation
• Own the full model lifecycle from research to production, including data analysis, model development, and A/B testing
• Partner with product managers, data scientists, and designers to deliver user-facing improvements
• Translate emerging research into scalable, production-ready systems

Requirements

• 5+ years of experience building and scaling ML/AI models for large-scale products
• Proficiency with AI coding tools (e.g., Claude Code, Cursor)
• BS, MS, or PhD in Computer Science, Engineering, or a related field
• Deep expertise in deep learning, LLMs, information retrieval, ranking, or NLP
• Strong programming skills in Python, Java, or C++
• Hands-on experience with PyTorch, TensorFlow, or XGBoost
• Extensive experience in the full ML lifecycle including feature engineering and monitoring

Preferred Qualifications

• Experience with LLM-based systems, prompt engineering, and RAG architectures
• Experience with Generative RecSys
• Experience solving large-scale personalization problems including user modeling and retrieval
• Contributions to the ML community via open-source or research publications

About the Company

DoorDash is a technology and logistics company on a mission to empower local economies. We are growing rapidly and expanding into new verticals like Grocery and Retail, reshaping how modern AI impacts marketplace relevance.