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 their companion iOS app end-to-end. The company is building a first-of-its-kind wearable device that reads and interprets real-time emotional states, helping users develop emotional intelligence and achieve repeatable peak-performance states.

This is a high-ownership founding role — you will define the primary consumer touchpoint for a cutting-edge AI inference platform, bridging complex multi-signal model outputs with intuitive, polished mobile experiences. The team is small (under 10 people), moving fast, and has working prototypes already on users' wrists. The founding team includes ex-Apple hardware product design veterans.

The role is based in London (with flexibility for remote) and reports directly to the founding team. Visa sponsorship is not available for new applications; H-1B transfers may be considered where applicable. Candidates must hold existing work authorization in the UK or US.

What You'll Do

• Own the companion iOS app entirely — from architecture and development through deployment, iteration, and long-term maintenance.

• 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 performance standards.

• Make autonomous technical decisions as the founding mobile engineer, setting patterns and standards the team will scale with.

• Collaborate across time zones with a distributed team spanning London, San Francisco, and beyond.

What We're Looking For

Required:

• 3+ years of professional iOS development experience with Swift and a proven track record of shipping production-ready, consumer-facing 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, data modelling).

• Experience integrating machine learning model outputs or inference results into a mobile UX.

• Proficiency delivering polished, consumer-grade UI/UX with attention to performance and smooth user experience.

• Comfortable working independently across time zones in a remote or hybrid environment.

• Strong CS fundamentals and the ability to own technical decisions with minimal oversight.

Nice to have:

• Background building data-driven apps that surface complex model or sensor outputs to end users.

• Experience at a high-calibre consumer tech, fintech, or wearables company.

• Appetite for a founding-team role at a seed-stage company where your work directly shapes the product and organisation.

This role is not suitable for recent or fresh graduates.

Compensation & Benefits

• Base salary: ~$150,000 USD (US) / ~£75,000 GBP (London)

• Equity: Meaningful founding-team equity package (up to 1–2%)

• Seed-stage funding from a top-tier accelerator; angel and strategic investor round in progress

Location

• Primary office: London, United Kingdom

• Flexibility also available for remote work or presence in San Francisco

• Visa sponsorship: Not available for new applications. H-1B transfers considered where applicable. Candidates must have existing UK or US work authorisation.