I am building a fintech mobile application that must run smoothly on both iOS and Android from day one. The first milestone is rock-solid, PCI-compliant payment processing: users should be able to add cards, initiate one-off or recurring transactions, and view real-time confirmations inside the app. You are free to suggest your preferred cross-platform stack—whether it’s React Native, Flutter, or a truly native Swift/Kotlin split—so long as the final builds meet Apple App Store and Google Play submission requirements and keep performance tight. I will provide UI wireframes, brand assets, and the payment-gateway API keys; you will wire everything together, handle secure token storage, and return clean, well-documented code plus test suites. Acceptance criteria • Testflight and internal Android builds demonstrating successful card tokenisation and charge flow • 100 % passing unit & integration tests for the payment module • Clear setup instructions and a short Loom video walkthrough of the codebase Future phases may add investment tracking and budgeting, so structuring the project for easy expansion is a bonus I’ll value highly.