Senior Mobile Engineer (React Native) Developer - build the world's first conversational private bank

Our client is the world’s first conversational private bank.
They are building the smartest interface between customers and their money, providing the "unfair financial advantage" usually reserved for the ultra-wealthy.

Founded in January 2026 and backed by top European VCs, they are assembling a world-class team to deliver an AI-native banking experience built on transparency, simplicity, and trust.

Youmanista is recruiting several senior mobile engineers (React Native) for this early-stage company.

🧠 Your Mission
You will join a fast-moving team to build the AI brain behind the app. Everything you build will directly shape how customers interact with their finances.

🛠 Key Responsibilities

• Core application → Design, build, and operate the mobile applications that deliver bank’s core experience: account management, seamless transaction flows, real-time data synchronization, and intuitive user interfaces.
• Client architecture → Design and own robust, scalable mobile architectures. Define clear module boundaries, manage complex application state, and ensure a responsive, offline-capable experience across a fast-moving codebase.
• Performance & optimization → Build and maintain the foundation for a smooth, high-performance mobile experience: fluid UI rendering, efficient background processing, intelligent network data caching, and strict battery/memory management.
• Security & authentication → Implement and evolve secure authentication flows and local data storage. Think carefully about biometric integration, keychain/secure enclave usage, and protecting sensitive user data on a mobile financial platform.
• Reliability → Own the operational excellence of the mobile client: crash reporting, observability, automated testing, CI/CD pipelines, and seamless app store rollouts. You care deeply about the user experience after the app is downloaded.
• Collaboration → Work hand-in-hand with Product and Design teams to craft world-class, pixel-perfect UX, and coordinate with the Backend and AI Engineering teams to seamlessly integrate complex APIs and intelligence into the mobile app.
• Hiring → Help grow the team by interviewing candidates and shaping the technical assessment process.

🎓 Skills & Knowledge
Must Have: ✅

• Expert-level proficiency with AI coding tools, both assistive and agentic (Claude Code, Copilot, Cursor, or equivalent). You leverage them aggressively but never blindly.
• Expert-level TypeScript and React Native skills with a strong focus on scalable code architecture. You know how to structure large, complex applications for long-term maintainability and performance.
• Expert knowledge of building and deploying applications through Expo. You are deeply familiar with Expo Application Services (EAS), OTA updates, custom development clients, and navigating App Store/Play Store distribution.
• Hands-on experience managing complex application state using modern tools like Zustand or Jotai. You understand the nuances of global vs. local state in a high-security, real-time banking environment.
• Practical knowledge of React Native Reanimated and React Native Skia. You know how to build fluid, high-performance animations and custom UI components without sacrificing frame rates.
• High standards for code quality and reliability: You write rigorous unit tests, build robust e2e test suites with Maestro, and strictly enforce quality through linting, formatting, and scripting within CI/CD pipelines.
• Strong API integration skills: Consuming REST or gRPC, with a track record of handling network volatility, pagination, and robust error handling gracefully on the client.

Nice to Have: ✨

• Knowledge of ConnectRPC for building robust, type-safe API communications.
• Experience building native modules or custom Expo Config Plugins (bridging the gap between React Native and native iOS/Android code).
• Familiarity with advanced mobile security practices (biometric authentication, Secure Enclave/Keychain, root/jailbreak detection).
• Prior experience in a regulated industry (ex: finance, healthcare, legal, etc.).

👤 About You

For the job :

• 5+ years of professional experience in mobile engineering, with a track record of building and operating a large scale or complex mobile application.
• Total autonomy: you drive technical decisions, set the bar for quality, and help others reach it.
• You care about the whole lifecycle — not just writing code, but making sure it runs, scales, and is easy to debug.
• Thrive in early-stage environments where scope is broad, ambiguity is high, and ownership is real.
• Hungry for a real challenge: you're not looking for a comfortable seat, you want to build something that doesn't exist yet.
• Solid communication skills in English; French is a big plus but not required.

For the project :

• Frustrated by how traditional finance serves its customers, and motivated to break the mold to create something genuinely better for our users.
• Genuinely excited about building the best-in-class mobile experience that makes a trustworthy, AI-native bank possible.

📋 Interview Process
We aim to complete this within 2 weeks.
1. Discovery Call (30 min): Background, motivations…
2. Technical Deep-dive (1 hr): Production systems, data, and AI engineering.
3. On-site Pairing (2 hrs): Work with the team on a real-world problem.
4. Culture Fit: Coffee, lunch, or a drink to get to know the team.

🎁 Contract & Perks
• Contract: Full-time permanent (CDI).
• Salary: Starting from 80k+ euros (depending on experience) + BSPCE stock options.
• Remote: 3/5 days in our Paris office + 3 weeks per year full remote.
• Hardware: Best-in-class laptop + Unlimited Claude AI plan.
• Benefits: 100% covered health insurance & 100% Navigo pass coverage.