Kotlin E-commerce App Development

I need an experienced Android developer to create an e-commerce app using Kotlin. The app should include:

Key Features:
- User login/registration
- Shopping cart
- Payment integration

User Authentication:
- Email and password
- Google sign-in
- Facebook login

Ideal Skills and Experience:
- Proficiency in Android development with Kotlin
- Experience in building secure and user-friendly authentication systems
- Strong background in integrating payment gateways
- Familiarity with e-commerce app design and functionality

Please provide your portfolio and any relevant project experience.