Founding Engineer (Potential CTO)

ABOUT THE ROLE A fast-moving, seed-stage digital health company is looking for a Founding Engineer (potential CTO) to be the second technical voice on the team. This is a rare 0→1 opportunity to shape the full engineering direction of an AI-native mobile health platform that uses biosignal data and real-time coaching to help people manage chronic symptoms by improving autonomic nervous system health. You'll own the architecture, ship the first end-to-end AI product experience, define the engineering culture, and grow into a CTO role as the company scales. This is a deeply hands-on, in-person role based in New York City, San Francisco, or Montreal. WHAT YOU'LL DO - Serve as the founding engineer and de facto technical leader, owning both direction and execution. - Ship the v1 AI coaching experience end-to-end — from a React Native mobile app to frontier-model-backed inference and wearable integrations. - Architect and build the nervous system training AI 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 AI-powered QA and testing pipelines to enable safe, rapid 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). - Define and uphold engineering standards and culture as the team grows. WHAT WE'RE LOOKING FOR Dealbreakers (must-haves): - Proven experience shipping and operating Claude or other frontier LLMs in production (prompts, tool use, evals). - Ability and willingness to work in-person in New York, San Francisco, or Montreal. - 3+ years in mobile/full-stack engineering with demonstrated 0→1 consumer mobile app delivery to real users. Required skills & experience: - Fluency in React Native with full ownership of the mobile lifecycle (build, release, debug, monitor, iterate). - Experience with AI-native infrastructure where AI is integrated across layers, not bolted on. - Backend development in Node.js or Python with PostgreSQL and modern infra (Vercel, Fly, Render, or similar). - Comfortable moving across frontend, backend, infra, and AI layers with minimal handholding. - Experience with HealthKit, wearable APIs, or biosignal data (HRV, PPG, motion) in real-time contexts. - Founder mindset with prior first-engineer or early-stage startup experience and the ability to make hard tradeoffs. Nice to have: - Experience building AI-powered testing or evaluation pipelines. - Background or deep interest in nervous system science, somatics, neuroscience, or trauma research. - Prior experience as the first engineer at a startup. COMPENSATION & BENEFITS - Base salary: $170,000 - Equity: Meaningful early-stage equity offered (range up to $2M in potential value) - Opportunity to grow into a CTO title as the company scales Note: Visa sponsorship is not available for this role. LOCATION This is an on-site role. Candidates must be able to work in person in one of three locations: New York City, NY · San Francisco, CA · Montreal, Canada. Remote work is not available for this position.