Cross-Platform Mobile App Development

I'm looking for an experienced mobile app developer to create a cross-platform app for both iOS and Android. The project needs to be completed ASAP.

Ideal Skills and Experience:
- Proficiency in React Native or Flutter
- Strong background in mobile app development for both iOS and Android platforms
- Experience with backend integration and API development
- Knowledge of UI/UX design principles
- Ability to deliver high-quality code and documentation
- Strong problem-solving skills and attention to detail

Please provide a portfolio showcasing similar projects and an estimated timeline for completion.