Founding Engineer (Potential CTO)

This is a rare Founding Engineer (potential CTO) opportunity at a seed-stage, AI-native digital health startup focused on nervous system repair and chronic disease management. You'll be the second technical voice at the company - the person who turns a bold product vision into a production-quality AI mobile experience, and who defines the engineering culture and stack for the next decade.

You'll own the full technical journey: from shipping the first end-to-end AI coaching experience in a React Native app, to architecting the model and feedback loop that powers a real-time nervous system training coach using wearable biosignal data., * Serve as Founding Engineer and potential CTO, owning technical direction and day-to-day execution.

• Ship the AI coaching product v1 end-to-end - from a React Native mobile app to Claude-backed inference and wearable integrations.
• Architect and build an AI-powered nervous system training coach, including model design, prompt engineering, tool use, and evaluation pipelines.
• Translate biosignals (HRV, breath, motion, PPG) into a real-time personalized coaching layer.
• Build and maintain AI-powered QA and testing pipelines to enable safe, fast daily shipping.
• Own full-stack decisions across frontend, backend, infrastructure, and AI-native layers.
• Integrate iOS/HealthKit and wearable platforms (e.g. Apple Watch, Oura, Whoop, EEG headbands).
• Collaborate closely with the founding team on-site in Montreal, SF, or NYC.

Dealbreakers (must-haves):

• Production experience shipping and operating Claude or other frontier LLM-based systems, including prompts, tool use, and evals.
• Willingness and ability to work in-person in Montreal, San Francisco, or New York City.
• 3+ years in mobile/full-stack engineering with a track record of delivering 0 1 consumer mobile apps to real users., * Deep fluency in React Native with end-to-end ownership of the mobile lifecycle (build, release, debug, monitor, iterate).
• Experience with AI-native infrastructure where AI functions are integrated across all layers - not bolted on.
• Backend development in Node.js or Python with PostgreSQL and modern infra (Vercel, Fly, Render, or similar).
• Ability to move fluidly across the full stack (frontend, backend, infra, AI) with minimal handholding.
• Hands-on experience with HealthKit, wearable APIs, or real-time biosignal data (HRV, PPG, motion).
• Founder mindset: comfortable making hard tradeoffs, operating with high autonomy, and building from zero.

Nice to have:

• Experience building AI-powered testing or evaluation pipelines.
• App Store shipping experience - a consumer mobile app with real, active users.
• Background or genuine interest in nervous system science, somatics, neuroscience, or trauma research.
• Prior experience as the first or founding engineer at an early-stage startup.

• Base salary: $170,000 USD / year
• Early-stage equity commensurate with founding-team scope
• High-impact, high-ownership role with a direct path to CTO

Visa sponsorship is not available for this role.