Senior AI Engineer

About the role

This is a Senior AI Engineer opportunity with a Series B health tech business building an AI doctor that offers free AI consultations and low-cost physician visits. The role blends research and engineering to improve how the AI doctor reasons, learns, retrieves evidence and is evaluated, and it affects clinical decisions directly. You’ll design agentic clinical reasoning architecture, including verification, tool use, routing and escalation, build evaluation platforms, rubrics and simulations, and apply fine-tuning, distillation, reinforcement learning and preference optimisation. You’ll also build the search, retrieval and grounding systems tied to clinical decisions. No specific stack is listed; the work centres on LLMs, reinforcement learning and retrieval methods. The ideal candidate will have either an advanced degree and 3+ years of applied or research AI and ML experience, or 7+ years building ML systems with recent LLM work. Deep experience in at least two of agentic and reasoning systems, evaluation and rubric design, model training and reinforcement learning, or search and RAG is expected, alongside strong ML fundamentals and engineering skills. Published research, early-stage experience and clinical AI knowledge (HIPAA, FHIR, EHR, HL7) would be advantageous. This is a hybrid position in New York City or San Francisco. We're looking for someone curious, pragmatic, and eager to work across the stack with a small senior team. You'll own end-to-end delivery of major features, influence architecture, and mentor engineers.

What you'll do

• Ship customer-facing features on a weekly cadence.
• Partner with design and product on scoping and trade-offs.
• Drive technical quality through review, testing, and docs.
• Mentor one or two engineers on your team.

Requirements