Founding Full-Stack iOS Engineer

### About the Role A Y Combinator-backed consumer wearable AI startup is hiring a **Founding Full-Stack iOS Engineer** to own the company's companion iOS app from the ground up. This is a high-ownership, founding-team role at the intersection of consumer hardware, real-time AI inference, and emotional intelligence. The company is building a first-of-its-kind wearable that reads and interprets a user's emotional state in real time — think a fitness tracker, but for your emotions and cognitive performance. You'll be the primary builder of the consumer-facing mobile experience, translating sophisticated AI model outputs (energy, mood, focus signals derived from audio and biometric data) into intuitive, beautiful interfaces. This role comes with significant equity upside and a clear path to leading mobile engineering as the company scales. The team is distributed, with presence in **San Francisco** and **London**. This role is based in **London**, with flexibility for hybrid or remote working arrangements. ### What You'll Do * Own the companion iOS app end-to-end — architecture, development, deployment, and ongoing iteration. * Surface real-time emotional-state outputs from the company's proprietary AI inference model through clean, intuitive app interfaces. * Build and ship a polished, consumer-grade mobile experience that meets high product and design standards. * Integrate backend APIs covering authentication, data sync, and data models. * Make autonomous technical decisions as a founding engineer, setting patterns and standards for the mobile codebase. * Collaborate across time zones with a small, fast-moving distributed team. ### What We're Looking For **Required:** * 3+ years of professional iOS development experience with **Swift**, with 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 mobile app development and backend API integration. * Experience integrating machine learning model outputs or inferences into a mobile app UX. * Ability to deliver polished, consumer-grade UI/UX with attention to performance and smoothness. * Comfortable working independently and across time zones as part of a remote/hybrid team. * Work authorization to be employed in the **UK or US** — the company does not offer new visa sponsorship (H-1B transfers considered where applicable). **Nice to Have:** * Background in data-driven apps that surface complex model outputs through accessible design. * Experience at a consumer hardware, wearable, or health/wellness tech company. * Strong CS fundamentals and comfort owning architectural decisions autonomously. ### Compensation & Benefits * **Salary:** ~$150,000 USD (US) / ~£75,000 GBP (London) depending on location * **Equity:** Meaningful founding-team equity (up to 1–2%) * Seed-stage company backed by a top-tier accelerator * High-ownership founding role with a clear path to leading the mobile engineering function ### Location Primary location: **London, United Kingdom**. The team also has a presence in San Francisco, CA. Hybrid and remote flexibility available for the right candidate. **No new visa sponsorship** — candidates must have existing UK or US work authorization (H-1B transfers considered). Find more [English Speaking Jobs in United Kingdom](https://www.arbeitnow.co.uk/english-speaking-jobs) on Arbeitnow