Founding Engineer | 👨🏻‍💻 AI-Native Mental Health Care (backed by Y Combinator, $3.3M+ ARR, $7M+ raised)

Legion Health is building autonomous mental healthcare powered by AI, aiming to improve patient experiences from scheduling to treatment. The Founding Engineer will own core product and agent systems, coordinating patients, clinicians, and AI agents to create an efficient care system.

Responsibilities:

• 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