E-commerce App Development

I need a skilled mobile app developer to create an e-commerce app with the following requirements:

Core Features:
- User Authentication: Secure login and user management.
- Product Catalog: Comprehensive listing of products.
- Shopping Cart/Checkout: Seamless shopping experience.

Payment Methods:
- Cash on Delivery
- QR Code Payments

Ideal skills and experience:
- Expertise in mobile app development (iOS and Android)
- Experience with e-commerce applications
- Strong knowledge of secure payment integration and user authentication protocols
- UI/UX design skills for an intuitive user experience

Please provide a portfolio with relevant work. Looking forward to your proposals!