React Native Mobile Developer

3.10 Role Overview

Headcount    1
Reporting to    Technical Lead (DaaS Labs)
Seniority    3-6 years; junior-to-mid per Nick Green's guidance
Repository    FT Mobile (Expo React Native 0.76+, Legend State, iOS + Android)
Critical flag    Observable/reactive state management is the primary screening gate

3.11 Functional Requirements

The Mobile Developer owns the FT field crew application — the tool that foremen and laborers use on-site to clock in/out, log safety documents, track tasks, and submit timesheets. This app must work offline in areas with poor connectivity and sync reliably when reconnected.

•    Develop and maintain cross-platform iOS and Android features in the Expo React Native codebase
•    Support BYOD (Bring Your Own Device) compatibility — the app must run reliably on personal employee devices across mixed iOS and Android versions
•    Implement offline-first functionality — local data persistence, sync queue management, conflict resolution
•    Build geolocation-based features — clock-in/out with GPS validation
•    Integrate NFC hardware via react-native-nfc-manager for badge-based attendance
•    Implement camera capture for safety documentation (JSP photos, EIS documents)
•    Build smooth, intuitive mobile UI using React Native Paper (Material Design)
•    Ensure the app performs consistently across both iOS and Android platform guidelines
•    Integrate with the FTApi via Axios — handle network failures gracefully
•    Implement analytics via Azure Application Insights and Microsoft Clarity
•    Manage app builds and store submissions via EAS Build (Expo Application Services)
•    Collaborate with QA engineers on test coverage and device compatibility validation
•    Write unit and component tests using Jest and React Native Testing Library

3.12 Technical Requirements

Core Stack — Required
•    React Native 0.76+ — must be the current major version; outdated RN experience (0.6x or earlier) needs explicit validation
•    Expo SDK 52+ with bare workflow — must understand the difference between managed and bare Expo
•    React 18.3+ — hooks, functional components, performance optimization
•    TypeScript / ES6+ — TypeScript required, not optional
•    React Navigation 6+ — Stack, Bottom Tabs, Material Top Tabs navigators

State Management — CRITICAL SCREENING REQUIREMENT
This is the single most important technical screening criterion for this role. Candidates must demonstrate practical understanding of observable/reactive state patterns — theoretical familiarity is not sufficient.

•    Legend State — preferred; production experience is ideal, close familiarity is acceptable
•    MobX — strongly preferred if Legend State experience is not available
•    Zustand — acceptable; demonstrates reactive state thinking
•    Vue.js (reactivity model) — acceptable signal of reactive state understanding per Nick Green's guidance
•    RxJS with observable streams — acceptable; demonstrates the underlying reactive paradigm
•    Signals (native or framework-level) — acceptable; BSW explicitly includes this in observable experience
•    NgRx (Angular) — some credit; shows observables literacy, but Angular-to-React-Native gap must be assessed
•    Redux only — does not meet the requirement; must demonstrate reactive state understanding separately
•    Recoil only — insufficient; US Client rated this as 'familiar' rather than production observable experience

Device Integration — Required
•    Expo Camera — photo capture for safety documentation upload
•    react-native-nfc-manager — NFC badge reading for attendance
•    Location services — GPS for geofenced clock-in/out
•    AsyncStorage — local data persistence for offline mode
•    File system operations — PDF viewing, document attachment handling

Networking and Offline — Required
•    Axios for API integration with proper retry and timeout handling
•    Offline-first architecture — must be able to describe a concrete approach to local-first data with background sync
•    Real-time data sync patterns — must have shipped at least one feature with background sync or push state

Build and Deployment — Required
•    EAS Build — Expo Application Services build pipeline for iOS and Android
•    App Store (Apple) and Google Play submission process — must have shipped to both stores

Additional Skills — Preferred
•    React Hook Form with Zod schema validation
•    Azure Application Insights SDK for React Native
•    Microsoft Clarity mobile integration
•    React Native Paper component library
•    Detox or equivalent end-to-end mobile testing

What Will Not Pass US Client Evaluation
•    React Native experience limited to convention component/navigation/REST patterns with no state management beyond Redux or Context
•    Only web React experience with no native mobile shipping history
•    Expo managed workflow only — the FT app uses bare workflow
•    No App Store or Google Play submission experience 
4.2 Mandatory Screening Gate — Mobile Role

Before any React Native candidate progresses to a client interview, they must demonstrate one of the following in a phone screen:

•    Can describe production use of an observable/reactive state library (Legend State, MobX, Zustand, RxJS, Signals, or Vue.js reactivity model)
•    Can explain the conceptual difference between push-based (observable) and pull-based (Redux selector) state models
•    Can walk through how t