E-commerce App Development

I'm looking for an experienced mobile app developer to build an e-commerce app available on both iOS and Android platforms. The app should integrate a payment gateway and offer real-time order tracking.

Key requirements:
- Payment gateway integration
- Real-time order tracking
- Available on both iOS and Android

Ideal skills and experience:
- Proven experience in developing e-commerce apps
- Strong knowledge of payment gateway integration
- Familiarity with real-time tracking technologies
- Proficient in both iOS and Android app development

Please provide samples of previous work.