Software Engineer — Patient Products (backed by Y Combinator, $5M+ ARR, $23M+ raised)

🧠 ABOUT LEGION HEALTH At Legion Health https://legionhealth.com/, we believe everyone deserves fast, affordable, and world-class health care, and we’re developing the AI infrastructure to deliver it ourselves at world scale. Legion is building autonomous medical care (the AI doctor), starting with psychiatry. Our AI-native care-delivery platform currently automates 95% of the administrative work required for us to deliver direct patient care. We also recently became the first company ever to receive regulatory authorization to let AI prescribe psychiatric medications https://nypost.com/2026/03/27/business/artificial-intelligence-can-now-prescribe-mental-health-drugs/, allowing us to not only collapse health care’s admin costs but also its clinical labor costs—shifting this industry’s economics from humans to tokens. Our technical moat is hard to copy—we combine rich data, production AI, doctors in the loop, and end-to-end care operations to deliver measurably better care to a clinically complex patient population. This has helped us produce tens of thousands of total visits in just 2 years, all while holding ops costs flat and achieving industry-leading patient NPS and retention. While the last generation of healthcare startups made the existing system incrementally more efficient, Legion is rebuilding full-stack care delivery from first principles. Our vision? A 10X better patient experience that’s higher quality, less expensive, and more scalable than ever before. And a 10X better clinician experience that frees our providers to focus on what matters most: caring for patients. Legion Health is backed by Y Combinator, leading venture capital firms, and founders from Function Health, Modern Health, Everly Health, Trusted Health, Clipboard Health, PatientPing, Sesame Care, Faire, EasyPost, and fuboTV. Join us as we build the future of health care: faster, higher-quality, and more affordable, powered by doctors and AI working together. 🚀 ROLE: ENGINEER – AI-NATIVE MENTAL HEALTH CARE (IN-PERSON IN SF) Hey—I’m Daniel Wilson https://www.linkedin.com/in/danielgwilson/, co-founder & CTO at Legion. I studied applied math + CS at Princeton, then led the Office Scripts + Power Automate integration at Microsoft—shipping the highest retention-driving feature in the product. Before that, I did deep learning + RL research. I’m obsessed with building AI systems that make real workflows cleaner, safer, and more autonomous. Github: https://github.com/danielgwilson I’m hiring a cracked Software Engineer to own core product + agent systems end-to-end. You’ll build the layer that coordinates patients, clinicians, and AI agents as one coherent machine—tight feedback loops, high standards, and real ownership. This isn’t “just infra.” It’s building the product heart of an autonomous care system: the workflows, the agent behaviors, the guardrails, the integrations, the UX that makes it usable, and the reliability that makes it trusted. Roles evolve quickly here—including mine. I’m looking for someone who wants to carry real weight, take full ownership, and grow into running major parts of the system—not someone who needs a perfectly scoped box to operate inside. ✅ WHAT YOU’LL DO - Own our event-driven backend – Architect and scale our Node.js / TypeScript / Supabase (Postgres) / AWS stack. Design schemas, invariants, and workflows that encode how psychiatric care actually operates. Turn messy real-world processes into clean state machines and event streams. - Build real LLM agents as coworkers – Implement tool use, retries, memory, and safety rails. Design action schemas and evaluation loops so agents can run reliably in production. Work on orchestration, context management, and multi-step workflows. - Shape human + AI ops UX – Build internal tools used by both humans and agents. Make it trivial to see “what happened, why, and what should happen next” in any patient journey. - Define world-state & simulation – Model the canonical state of a patien…