Android & iOS Ordering App

I’m developing a mobile application that must launch on both Android and iOS from a single code-base. Core functionality includes:

• Secure user login
• Credit/Debit Card Payment integration (Stripe, Braintree, or a comparable PCI-compliant SDK)
• Order tracking with:
– Real-time location tracking
– Order status updates

The interface should remain clean and responsive, and the back-end endpoints for authentication, payments, and tracking will be provided (or you can quote for building them if that’s your preference).

Please outline:
1. Your suggested tech stack (e.g., Flutter, React Native, Kotlin/Swift separately, etc.) and why it fits.
2. A high-level milestone plan with estimated timeline for each phase.
3. Total cost and anything that might influence it (third-party fees, hosting, post-launch support).
4. Any similar apps you’ve launched that demonstrate payment processing and live tracking.

All delivered code must be production-ready, well-commented, and handed over in a private Git repository. Let me know if anything needs clarification—looking forward to your proposal and timeline.