Founding Mobile App Developer -Stealth Music-AI Startup
San Francisco | $120K–$200K + Equity | Visa Sponsorship Available
My client is building the "Shazam for sheet music." Upload any audio or YouTube link, get back accurate sheet music, MIDI, MusicXML, Guitar Pro tabs, or an interactive piano roll — across nine instruments. Their proprietary transcription AI cracked an audio-to-MIDI problem that stumped music-information-retrieval research for decades.
The traction speaks for itself: 150,000+ users across 150 countries, 60% month-over-month growth, entirely organic with zero marketing spend.
Backed by a $5M seed round led by a top-tier education/consumer VC fund (with several other institutional investors and a well-known angel from the music industry on the cap table), the company came out of Stanford's StartX accelerator. Founded by a Stanford MBA CEO and a technical CTO whose music-AI research underpins the core product. Their second product is an iOS app that teaches songs through a real-time piano roll.
THE ROLE
They're hiring a Founding Mobile App Developer to own the mobile experience end to end. Right now the app is iOS-only with zero redundancy — when the CTO steps away, mobile stalls. This hire changes that: full ownership of the mobile codebase (iOS now, Android next), starting with bringing transcription to mobile, then building a new AI-native learning app on the company's proprietary models.
This is a product-leaning, full-stack role. You'll need to be self-sufficient on the backend, but design and product instinct are what get weighted hardest — especially for an app that lives in someone's hand, where haptics and feel have to be great. Swift depth matters less than it used to; taste, speed, and product sense are what count now that AI coding tools have lowered the bar.
WHAT YOU'LL OWN
- Mobile development from zero to one — the entire codebase for iOS (now) and Android (next)
- Core infrastructure: database architecture, authentication, payments
- Shipping fast — turning specs and design mocks into production at speed, then refining on real user feedback and usage data
- The full mobile UX — haptics, feel, and the "make it nice" bar
- Guiding junior devs and shaping mobile engineering culture as the team grows
- Being the redundancy — keeping the app moving without the CTO in the loop
WHAT THEY'RE LOOKING FOR
- Product-leaning full-stack mobile developer — happiest in product/frontend, competent on backend
- Full mobile stack: React Native / Swift / Kotlin (or similar), Next.js, Tailwind, backend-as-a-service (Supabase strongly preferred), auth, payments, DB design, API integration
- Strong design and product intuition — genuinely cares about what makes a mobile experience delightful
- Ships fast and translates specs/mocks into production code at speed
- First-principles thinker who reasons well and pushes back constructively
- Shipped consumer mobile apps with real, meaningful user bases
- 0–4 years' experience — weighted on the quality of what you've built, not tenure (sweet spot ~1–2 years, but near-zero experience is fine if the work is strong)
- Can own the app end to end with no hand-holding
NICE TO HAVE
- Musical experience or a genuine passion for music (no conservatory-level rigidity required)
- Familiarity with music transcription and formats like MIDI or MusicXML
- Game development or learning-software experience, especially in music
- A multidisciplinary, high-IQ generalist background — didn't stay in one lane
- Consumer-app pedigree with a clear track record of caring about polish
If you want to learn more, please apply below and I will be in contact to discuss the role further.