The Senior Machine Learning Engineer will join the Agentic Foundations team at DoorDash, focusing on Vertical Agent Development. This role involves improving flagship agents like the Ask Assistant through an eval-driven loop to enhance speed, cost-efficiency, and reliability for customers. The engineer will collaborate with teams on agentic memory and product representations, ensuring that insights from production agents inform foundational work. This position offers a hybrid work environment and the opportunity to impact the grocery and retail delivery business significantly.

• 3+ years of industry ML experience, including hands-on work building and shipping LLM-based agents.
• Experience with post-training or fine-tuning of open-weights models, ideally including small language models.
• Strong foundation in NLP and machine learning, with proficiency in Python and frameworks such as PyTorch or TensorFlow.
• M.S. or PhD in Computer Science, Statistics, Math, or another quantitative field, or equivalent practical experience.

• Build and refine the eval harness-optimization loop to identify failure modes and iterate on improvements.
• Run rigorous experiments to balance quality, latency, and cost in agent performance.
• Launch new agents for Merchants and Dashers from early exploration to production.
• Collaborate with teammates on agentic memory and product representations to enhance generative recommendations.
• Partner with engineering, product, and business leaders to define an ML-driven strategy for the grocery and retail delivery business.