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

• 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 patient’s journey across time. Power alerting, routing, and decision-making from that live simulation.
• Own data, safety & compliance - Engineer HIPAA-compliant pipelines for transcripts, events, and EHR data. Ensure PHI access, agent actions, and human overrides are all auditable.
• Drive architecture & strategy - Work directly with me to debate tradeoffs, define new primitives, and decide what we build next.

You don’t need to be a pure backend engineer-we value great product engineers who can learn fast, make strong simplifying decisions, and grow into owning backend/agent systems.

You Might be a Fit If…

• You’ve owned real systems 01 or 1N, not just tickets.
• You think in events, state, and invariants, not just CRUD endpoints.
• You’re either already LLM-fluent or a strong systems/backend engineer who can get dangerous fast.
• You care about velocity and correctness-moving quickly while keeping things understandable and robust.
• You like small, high-candor teams and direct feedback.
• You want to see your work go live in production weekly, not sit on a roadmap.

• Experience with Node.js / TypeScript, Postgres, or Supabase.
• Experience with LLMs, agents, tool-calling, or RAG.
• Experience in healthcare, fintech, or other regulated / high-stakes domains.
• Experience in early-stage startups or founding teams.

• Time Off: Flexible, unlimited vacation policy
• Work Hours: Flexible but demanding because we’re literally saving lives
• Work Setup: In-person @ San Francisco HQ
• Impact: Work on something that truly matters to millions of patients and families.
• Autonomy and Learning: Ownership over your projects with the freedom to set priorities, shape processes, and drive outcomes end-to-end.
• Growth Opportunities: As we scale, we envision our top performers stepping into expanded roles and joining our executive leadership team.

At Legion Health, 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, 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.

Engineer - AI-Native Mental Health Care (In-Person in SF)

Hey-I’m Daniel Wilson, 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.