Fintech Investment Management Mobile App Development

I'm looking for a seasoned developer to create a secure, user-friendly iOS and Android app for managing investments as a part of a larger fintech platform. The app will use REST API to integrate with our server and should be designed with careful consideration towards data handling.

Key Aspects:
- The app will focus on cash transaction, payments and portfolio.
- It will need to handle real-time balance, so knowledge of integrating with finance APIs is a plus.
- The app should be built with security as a top priority, employing OAuth2 for user authentication.
- Careful data handling is paramount. The app should load data locally when possible and only call the REST API when necessary, potentially utilizing background refresh techniques.

Ideal Skills and Experience:
- Proven experience in mobile app development, specifically within the fintech sector.
- Strong understanding of REST API integration and server communication.
- Prior work with OAuth2 and implementing secure systems.
- Experience in designing apps with careful data handling and local data storage.
- Familiarity with investment management features and tools.

UI Design is ready we just need developer to make the app and connect with our server

The selected freelancer will be responsible for testing all app functionalities against the REST API server to ensure seamless integration and performance. If you have the skills and experience to bring this project to life, I look forward to hearing from you.