We’re looking for a Senior Freelance Engineer (Mobile + Backend) to partner directly with the founder in building a scalable, data-driven system in the Digital Health / Femtech space.

This is a long-term, strategic collaboration with real influence on architecture, product direction, and system design with the potential for equity participation.

Tasks

• Analyze and evolve existing systems into a clean, scalable architecture
• Own system design across mobile and backend, including data models and core logic
• Ensure robust integration between mobile and backend systems
• Lay the technical foundation for future features, algorithms, and product growth, and the evolution of business logic
• Communicate decisions clearly and transfer knowledge to founder to enable long-term system ownership

Requirements

• Seniority: 5–8+ years of experience in real product environments with strong engineering standards (testing, code quality, production readiness)
• Strong experience with React Native, TypeScript, and mobile architecture
• Advanced backend expertise (AWS)
• Proven experience designing scalable architectures and refactoring complex systems, including modeling complex, state-driven systems and data logic
• Experience with data modeling, system design, and data-driven or algorithmic products
• Solid understanding of GDPR and handling sensitive data
• Interest in (female) health and hormonal systems
• Experience in digital health startups

Benefits

• Flexible, remote-first work
• Personal coaching support
• Meaningful work: direct impact on women’s health through product and system design
• Fair, structured compensation and a long-term perspective for strong collaboration

How You’ll Work: Freelance setup (individual or max. 2 people) 10–20 hours/week, working directly with the founder with a collaborative style that includes independent ownership, pair programming, code reviews, and architecture discussions.

Please send:

• Relevant projects (especially refactoring and system design/building)
• A brief description of your approach to working with complex codebases
• GitHub, code samples, or other insights into how you work

Find Jobs in Germany on Arbeitnow