Senior Product Engineer - Mobile Developer (L3)

What this role is

The market has no shortage of mobile developers who only do mobile, and no shortage of full-stack engineers who have never shipped a production app. This role is neither of those.

You are a Product Engineer whose centre of gravity is mobile. React Native is where you live. You have shipped apps, debugged native integrations, handled platform-specific edge cases, and understand what it actually takes to get something through App Store and Play Store review. That is the non-negotiable foundation.

But at Fountane, Product Engineers build products — not layers. The same feature that lives in a mobile app often has a web surface, an API, a webhook, or a database schema behind it. At L3 you are expected to own the full application surface of what you are building, not hand off the moment the work touches a backend. You will not be doing everything alone — you have a pod. But you will need to be capable of crossing the boundary when the work demands it.

You are joining a permanent Island pod. Your first deployment is to an ongoing client engagement that requires your mobile depth immediately. After that, you are a long-term Islander who will move across engagements as the Mainland deploys you.

What Fountane is actually asking for

We know the market has specialists. We are not pretending this is a standard full-stack role with mobile as a footnote, or a mobile role where full-stack is irrelevant. Mobile is your primary skill. Everything else is your secondary obligation. If you have spent your career going deep on React Native and can hold your own on an API or a web feature when needed, this role fits you.

If you are a pure mobile specialist who cannot — or will not — touch anything outside the app layer, this is not the right fit. Not because we do not respect specialisation, but because Islands do not have room for hard walls between disciplines. The work crosses boundaries. So must you.

What you will own at L3

• React Native application development — the primary mobile codebase, feature delivery, and platform-specific implementation across iOS and Android
• App Store and Play Store release management — build pipelines, submission, review compliance, and versioning
• Native integrations — push notifications, device permissions, biometrics, deep linking, offline-first patterns, and platform SDK integrations where required
• Context Engineering — translating Concept Engineer prototypes and briefs into a clean, scalable mobile architecture using Cursor as your primary execution tool
• API integration and backend contribution — consuming and, where needed, building or modifying the backend services your mobile surfaces depend on
• State management architecture — owning how data flows through the mobile application, not just implementing patterns handed to you
• Cross-platform consistency — ensuring iOS and Android behaviour is intentional and documented, not accidental
• Cursor .cursorrules contribution — maintaining the Island's mobile-specific coding standards and context files so the codebase stays navigable as it grows
• Refactoring and codebase stabilisation — at L3 you are expected to work safely on an existing codebase, not just greenfield. You use Cursor's codebase context to edit and optimise without breaking what already works
• Mentoring L1 and L2 engineers on the Island — reviewing their code, raising the quality bar, and making sure mobile-specific patterns are being applied correctly across the pod

The technology you will be working with

This role is being hired for a specific active engagement. The following is the technology stack in use on this project. If you have not worked with these directly, do not apply.

• React Native — cross-platform mobile, iOS and Android
• TypeScript and JavaScript (ES6+) — the entire codebase is typed
• State management — Zustand and Redux; you need to know both and have an opinion on when to use each
• API integration — RESTful APIs and GraphQL; you will be consuming both
• Push notifications — Firebase Cloud Messaging (FCM) and Amazon SNS
• List rendering and UI performance — FlatList and related React Native optimisation patterns; this is not optional on a project of this scale
• Git — branching, PR reviews, and version control discipline on a team codebase
• iOS and Android platform guidelines — you understand the design and behavioural expectations of both platforms and implement accordingly

Bonus — useful but not required to apply:

• Native Android (Kotlin/Java) or iOS (Swift/Objective-C) experience
• Mobile testing frameworks — Jest, Detox, React Native Testing Library
• CI/CD pipeline experience for mobile applications
• Performance monitoring and analytics tooling

Proof-based qualifications

We do not assess candidates on years of experience or job titles. We assess on proof of capability. When you apply, be prepared to demonstrate the following:

What we look at

What you must show

2–3 shipped apps

Live applications on the App Store and/or Play Store that you built or were a primary engineer on. Provide links or app names in your application. We will look them up. If you cannot name two shipped apps, do not apply.

React Native + TypeScript

A codebase or feature set demonstrating typed React Native development — components, hooks, context API, and state management using Zustand or Redux. Not a tutorial project.

API and backend integration

A feature where your React Native work connected to a RESTful or GraphQL API — ideally one you also built or modified on the backend side. Show us the integration, not just the consumption.

Cursor-driven workflow

Walk us through how you currently use Cursor and Claude in your build process. Not a demo. A real conversation about how AI tooling has changed how you write and debug code.

A CV listing React Native and a GitHub with no shipped apps is not proof. Show us what you have built.

AI tooling at Fountane

Claude and Cursor are the primary tools for thinking, drafting, and executing work at Fountane. Every Product Engineer — including this one — is expected to use Cursor as their main development environment and Claude for context engineering, debugging, and architectural thinking.

This is not a listed skill. It is the working method. If you are not already building with Cursor and Claude integrated into your daily workflow, you will need to get there fast. The Island's velocity depends on it.

Who should not apply

• You have only built mobile apps backed entirely by third-party services (Firebase, Supabase) and have never touched application logic outside the app layer.
• You cannot name two or more applications you have shipped to the App Store or Play Store.
• You treat mobile as a skin over a web app. You have not handled platform-specific native behaviour, device APIs, or cross-platform edge cases.
• You are not using AI tooling in your current workflow and see it as optional.
• You need a clear boundary around mobile and expect the backend work to always belong to someone else.

What comes next

L3 is not a ceiling. The path to Lead PE — Mobile requires demonstrated ability to orchestrate the Island's full application architecture across mobile and backend, define the .cursorrules for the pod, manage Island velocity, and handle client technical conversations without the Lead CE in the room. Promotion is not tenure-based. It is triggered by demonstrated capability at the next level's complexity tier.

About Fountane

Fountane is a technology ventures lab - one part product studio, one part startup engine. We build high-quality software and AI products for clients ranging from fast-moving startups to large enterprises, and we co-build and invest in new companies when we see the right opportunity.

Founded in 2017 and headquartered in Minneapolis, we have grown to 60+ people across four continents and were recognised as one of America’s fastest-growing companies, ranking No. 699 on the Inc. 5000 with 595% three-year growth.

We are radically open-minded, serious about craft, and direct about expectations. If you want to do meaningful work without politics, this is the place.