E-commerce App Development for iOS & Android

I'm seeking an experienced app developer to create a comprehensive e-commerce app available on both iOS and Android platforms.

Core features to include:
- Product catalog
- Shopping cart
- Payment gateway integration

Ideal Skills and Experience:
- Proven experience in developing e-commerce apps
- Expertise in both iOS and Android platforms
- Strong knowledge of payment gateway integrations
- Familiarity with user-friendly UI/UX design principles

Please share your portfolio and relevant experience.