Freelancer Senior Mobile Engineer (React Native, Expo, TypeScript) m/w/d

About This Opportunity

We are representing a confidential SaaS client in their search for a Freelance Senior Mobile Engineer specializing in React Native, Expo, and TypeScript. Our client serves over 22,000 businesses with their core platform and is now expanding their mobile presence on iOS and Android. You'll join at an exciting stage where foundational features exist, but the product architecture and roadmap are still being shaped.

This is a hands-on senior role where you'll make technical decisions, build user-facing features, and own the mobile experience end-to-end. You'll work closely with a focused team that values clear priorities, clean solutions, and pragmatic execution.

Responsibilities

You will develop and evolve the mobile application built on React Native, Expo, and TypeScript for iOS and Android. The app already includes authentication, a dashboard, and document overviews—you'll build on this foundation and shape what comes next.

• Translate business requirements around invoicing and documents into intuitive mobile workflows and high-quality native interfaces
• Advance the app architecture with maintainable patterns for navigation, reusable components, forms, and data access
• Integrate REST APIs with typed interfaces, validation, caching, loading states, and comprehensive error handling
• Work at the intersection of mobile and backend—when needed, extend REST API endpoints using PHP and Symfony to support new mobile features
• Implement secure authentication, session management, and careful handling of sensitive business data
• Monitor performance and platform-specific behaviors across varying network conditions, app states, and devices; ensure accessibility and multi-language support
• Secure changes with automated tests; validate behavior on simulators and physical devices
• Shape build, release, and monitoring processes through App Store publication
• Challenge requirements, propose solutions, and guide features from concept through release and iteration
• Use AI development tools like Claude Code extensively while maintaining responsibility for quality, clarity, and correctness of outputs

Technology stack: React Native, Expo, Expo Router, TypeScript, TanStack Query, TanStack Form, Zod, NativeWind, Jest, React Native Testing Library. The existing platform and REST API are built with PHP and Symfony.

What We're Looking For

You don't need to know every library in advance. What matters is that you understand your stack deeply, make sound technical decisions, and learn independently.

• Senior-level experience with TypeScript, React Native, and Expo—you've shipped mobile applications through to release, not just implementation
• Strong grasp of React fundamentals: component architecture, state management, asynchronous data flows, and structuring complex systems clearly
• Understanding of iOS and Android platform differences; systematic approach to performance issues, platform bugs, and debugging
• Confidence integrating REST APIs with proper understanding of contracts, authentication, validation, and error handling
• Ideally, working knowledge of PHP and Symfony—able to read existing API endpoints, troubleshoot app-backend issues, and extend interfaces independently
• Commitment to automated testing, well-reasoned technical decisions, and maintainable code as standard practice
• Self-directed and pragmatic work style with clear communication and focus on end-user value
• Fluent German and good English

Bonus points: Experience with EAS, native modules in Swift or Kotlin, App Store publishing and mobile release processes, published apps of your own, open-source contributions, or public experiments on GitHub.

If you don't check every box but you're an exceptionally strong engineer, apply anyway and show us what you've built. We're particularly interested in projects where you held technical responsibility: what you built, what decisions you made, and what you learned.

How We Work With You

Candidates apply directly through Get A Job.ai. Our talent team will conduct an initial screening to understand your background and technical experience. Once we identify a strong match, we'll submit your profile to our client for consideration. Please do not contact the client directly—all communication flows through our recruitment process to ensure a coordinated and professional experience.

Pay

Compensation details will be discussed during the screening process based on your experience level and the freelance arrangement.

Work arrangement: Remote-first, freelance engagement. No location restrictions within Germany.

Equal Opportunity

Get A Job.ai is committed to inclusive hiring practices. We welcome applications from candidates of all backgrounds and work to ensure equitable access to opportunities.