Cross-Platform E-Hailing App Development

I'm seeking an experienced mobile app developer to create a cross-platform e-hailing app for both iOS and Android. The app needs to include the following core features:

- Ride Booking and Scheduling: Users should be able to book and schedule rides with ease.
- Real-Time Tracking: Implement GPS functionality for real-time ride tracking.
- Payment Integration: Secure payment gateway for transactions.

Ideal skills and experience:
- Proven experience in developing mobile apps, especially e-hailing or similar utility apps.
- Strong expertise in both iOS and Android platforms.
- Proficient in integrating secure payment systems.
- Knowledge of real-time GPS tracking technology.

Please provide a portfolio of your previous work and any relevant certifications. Looking forward to your proposals!