React Native Developer (Mobile App — Sports/Social Platform)

We're building a mobile-first social platform in the sports and fitness space, launching in London in Q2 2026. The app matches athletes with compatible training partners and enables group event discovery and club organisation. We're looking for a full-stack developer to own the backend architecture and take end-to-end responsibility for feature delivery.

This is not a greenfield project. We are approaching and seeking full time developers to manage the project post-launch and push further product improvements.

You'll be the primary developer responsible for backend logic, data architecture, and API integrations - while also being comfortable working across the React Native frontend when needed.

Core responsibilities include designing and maintaining Firestore data models and security rules; writing and deploying Cloud Functions (Node.js/TypeScript); building and optimising the matching algorithm that pairs athletes by sport, pace, location, schedule, and fitness data; managing third-party API integrations (Strava OAuth, Garmin, Onfido ID verification, RevenueCat); ensuring the backend scales cleanly as the user base grows across multiple cities; and collaborating directly with the founder on product architecture decisions.

Firebase (Firestore, Authentication, Cloud Functions), React Native (Expo managed workflow), TypeScript, EAS Build, RevenueCat. Design deliverables come from Figma.

Looking for:

• 3+ years building production applications on Firebase or similar serverless backends
• Strong TypeScript/Node.js - Cloud Functions are the backbone of the product
• Experience designing Firestore data models and writing security rules
• Comfortable with OAuth flows and third-party API integrations
• Able to work across the full stack
• Self-directed - you'll scope your own work with the founder, not receive pre-written tickets
• Bonus: experience with matching/recommendation systems, social platforms, or marketplace products