Founding Full-Stack iOS Engineer

About the Role This is a founding engineering role at a Y Combinator–backed wearable AI startup building a consumer device that reads and interprets emotional states in real time. You'll own the companion iOS app end-to-end — the primary touchpoint between sophisticated AI inference technology and the people who use it. As an early team member, you'll have real ownership and a direct hand in shaping the product as the company scales. What You'll Do Own the companion iOS app from architecture through deployment and ongoing iteration. Translate emotional-state outputs from an AI inference model into intuitive, meaningful app interfaces. Build and ship a polished, consumer-grade mobile experience that meets high product and UX standards. What We're Looking For 3+ years of professional iOS development experience with Swift , and a proven track record of shipping production-ready consumer iOS apps. Demonstrated end-to-end ownership of mobile features from concept through release and ongoing maintenance. Strong full-stack capabilities including backend API integration — authentication, data sync, and data modelling. Experience surfacing machine learning or AI model outputs within a mobile app UX. Ability to deliver polished, performant UI/UX with a strong eye for consumer-grade design. Strong CS fundamentals and comfort making autonomous technical decisions as a founding engineer. Able to work across time zones; comfort collaborating with a distributed team. Work authorization in the UK or US required — visa transfers may be considered, but new sponsorship is not available. Compensation & Benefits Salary of $150,000 USD (or approximately £75,000 GBP for the London office). Meaningful equity stake offered as a founding team member. No new visa sponsorship; visa transfers may be considered. Location On-site in London, England, UK (London office). Candidates based in San Francisco or fully remote may also be considered depending on fit.