Founding Full-Stack iOS Engineer

About the Role This is a founding engineering opportunity at a Y Combinator–backed consumer wearable startup operating at the intersection of biometrics, emotional intelligence, and mobile software. The company is building a wearable device that reads emotional states in real time — think of it as a fitness tracker, but for your EQ — powered by a proprietary computational neuroscience inference model processing over 150 audio and biometric signals. As the Founding Full-Stack iOS Engineer, you will own the companion iOS app end-to-end. This is a high-ownership, high-impact role: you'll be one of the first engineers at the company, expected to grow into a leadership position as the team scales. Prototypes are already on users' wrists — this is a real product with real momentum. What You'll Do Own the companion iOS app end-to-end, from architecture decisions to pixel-perfect UI delivery Surface emotional-state outputs (energy, mood, focus scores) from the backend inference model in a clear, compelling, and polished consumer experience Collaborate closely with the founding team — including hardware, neuroscience, and design — to shape the full product experience Build and maintain full-stack integrations between the iOS app and backend services Set engineering standards and best practices as the mobile org grows around you What We're Looking For Required Several years of professional experience shipping consumer-grade iOS apps (no fresh graduates) Strong proficiency in Swift and the iOS ecosystem Full-stack capability — comfortable working across mobile and backend layers Track record of owning and delivering polished, production-quality mobile products Self-directed and comfortable working in a fast-moving, early-stage environment Nice to Have Experience with health, fitness, or wearable consumer apps Familiarity with biometric data, Bluetooth/BLE hardware integration, or real-time data streaming Prior founding or very early-stage startup experience Compensation & Benefits Salary: ~$150,000 USD (or ~£75,000 GBP for London-based candidates) Equity: Up to 1–2% — meaningful founding-level ownership Early-stage company with Series A/B angel and strategic-partner funding round in progress Visa sponsorship: Not available for new sponsorships; visa transfers are welcome Location Primary office in London, United Kingdom. The team is also present in San Francisco. Flexible arrangements considered for the right candidate — on-site or remote.