Cross-Platform App Development

I need a skilled app developer to build a cross-platform app for both iOS and Android. I have a basic layout and a few images ready.

The app will require:
- User authentication
- Push notifications
- In-app purchases

Data to be collected includes:
- User data
- Location data
- Usage analytics

Ideal Skills and Experience:
- Proficiency in iOS and Android app development
- Experience with user authentication and push notifications
- Knowledge of in-app purchase integration
- Familiarity with data collection and analytics

Looking for someone who can bring my vision to life and ensure a smooth user experience. Please provide your portfolio and relevant experience.