Full Stack Developer - React Native / Expo / SpringBoot

> Location: Remote-friendly
> Contract: Full-time
> Salary: 58,000~68,000 Monthly

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1. The Challenge

We're looking for a developer who can move seamlessly between our React Native mobile app (Expo SDK 55, Zustand stores) and our Spring Boot microservices backend.

You won't just "touch both sides" - you'll own features end-to-end.

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2. What You'll Actually Build

Mobile Side (Expo / React Native)

- MMKV persistence, and type-safe component registries, push notification router, Deeplink & URL Routing

Backend Side (Spring Boot / Java)

- REST API Design: Clean, versioned endpoints for the mobile app to consume
- Authentication & Security: OAuth2 flows, JWT validation.
- Scheduled jobs and SFTP reconciliation
- Firebase Cloud Messaging orchestration
- Data Layer: SQL Server with Hibernate, QueryDSL, Liquibase migrations, JOIN FETCH optimization

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3. Tech Stack

Mobile Stack

Framework: Expo SDK 55, React Native 0.83, React 19.2

Language: TypeScript 5.9 (strict mode)

Navigation: Expo Router (file-based)

State: Zustand 4.5, TanStack Query 5.50

HTTP: Axios 1.7 + custom fetch wrapper

Forms: React Hook Form + Yup/Zod

Storage: MMKV, AsyncStorage, expo-secure-store

Maps: react-native-maps 1.27, clustering

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Backend Stack

Language: Java 17

Framework: Spring Boot 2.7, Spring Security, Spring Data JPA, WebFlux

Persistence: SQL Server (Azure), Hibernate, QueryDSL, Liquibase

Security: OAuth2, JWT

Messaging: Firebase Cloud Messaging, SendGrid

Resilience: Resilience4j (Circuit Breaker)

Testing: JUnit 5, Mockito, Jacoco

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4. Must-Have Requirements

Hard Requirements

Equipment:

- Mac computer (MacBook, Mac mini, or iMac) required for iOS app development and compilation

Mobile Expertise:

- 3+ years professional React Native with at least 1 year on Expo (managed + bare workflows)
- Deep TypeScript fluency , discriminated unions, mapped types, strict generics
- Production Zustand + TanStack Query experience
- Native module debugging, reading iOS/Android crash logs
- Push notification architecture, Expo Notifications, FCM, iOS/Android payload differences

Backend Expertise:

- 3+ years professional Java backend development
- Strong Spring Boot, Spring Security, Spring Data JPA
- SQL proficiency, query optimization, indexing, JOIN FETCH, avoiding N+1
- REST API design, versioning, pagination, HTTP semantics, OpenAPI
- OAuth2/JWT, flows, token lifecycle, refresh strategies

Full Stack Judgment:

- Experience designing APIs you later consumed (or vice versa)
- Understanding of mobile-backend contract design: what to cache, what to paginate, how to handle offline scenarios
- Debugging distributed features (logs, correlation IDs, network inspection)

Critical Soft Skills

- Reads code before writing it, The mobile codebase has 30+ stores; the backend has 100+ service interfaces. You trace data flow before proposing changes.
- End-to-end ownership, You don't hand off "backend work" or "frontend work." You ship the feature.

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5. Nice-to-Have (Separates Good from Great)

- Firebase expertise, Analytics funnels, Crashlytics, Cloud Messaging
- Open-source contributions to Expo, React Native, Spring Boot

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6. What You Won't Do

- ? Use Expo Go. We use development builds with custom native modules
- ? Ignore the database. You'll write and optimize SQL
- ? Skip tests. JUnit + Jacoco on backend

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7. Interview Process

Technical Test. We look for evidence of mobile depth

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