Senior Full-Stack Developer (React + React Native & TypeScript) (m/f/d)

As Filen continues to grow, we're looking for a Senior Full-Stack Developer / Senior Product Engineer to help us scale and evolve our product. You’ll be a key part of a small, agile team, working across the entire stack to build secure, privacy-focused cloud solutions.

It’s important for us to find someone who can work side by side at the highest level with our lead software developers.

Activities

What you’ll do

• Develop and maintain our cross-platform interfaces using React
• Refactor and modernize components to improve speed, usability and accessibility
• Use a diverse set of skills to improve and optimize the performance & design of our products & interfaces
• Collaborate closely with a small, agile team
• Take ownership of projects and features from concept to release
• Drive architecture and code quality (patterns, refactoring, maintainability)
• Be ready to contribute quickly after an fair onboarding period
• Improve performance & UX with measurable outcomes (Core Web Vitals, load times, responsiveness)

Requirements

Must-have

• Several years of production experience
• Excellent TypeScript skills (clean types, refactor-safe code)
• Solid experience with React & React Native, especially hooks and modern component patterns
• Understanding of responsive design and accessible web development
• Knowledge of performance optimization, accessibility best practices, and (testing) tools such as Vitest, Playwright, Maestro
• Ability to work independently, communicate clearly, and deliver end-to-end

Know or be ready to learn:

• React Query (@tanstack/react-query): comfortable working with queries, mutations, caching, and existing API hooks
• Zustand: able to work confidently with global state in an existing codebase
• Electron: familiar with building/maintaining cross-platform desktop apps
• Native mobile development: experience with Kotlin and/or Swift

We don’t care about degrees or certificates. We care about what you can build. If you have GitHub projects, a portfolio or side projects you’re proud of, we’d love to see them.

Team

We are a small, agile, international team, working across the entire stack to build secure, privacy-focused cloud solutions. Internal company communication is conducted in English, but most of the team also speaks or understands German.

Application Process

We always work efficiently and in a results-oriented way. The application process consists of two parts:

• An initial call where we discuss all organizational matters as well as your general experience
• A coding interview where we review your practical skills while you complete a simple task for us.
• If you are suitable, we would move directly into the onboarding phase / probation period.