Finance API Prototype & Beta App

I’m ready to turn my concept into a working software prototype that demonstrates a complete payments-processing flow through a finance API and then package that prototype as a beta mobile app for both iOS and Android.

The build should cover the core screens, wire them to the chosen payments endpoints (Stripe, Plaid, or a similar REST-based service), manage tokenisation and callbacks, and surface basic transaction status inside the app. While payments processing is the immediate focus, I’d like the codebase structured so we can layer in other financial features later without major rework.

I’m open to React Native, Flutter, Swift/Kotlin, or another cross-platform stack—whichever gets reliable TestFlight and Google Play Internal builds in the shortest time.

Deliverables
• Interactive software prototype showing the full payment flow (initiate → confirm → receipt)
• Beta builds: iOS (.ipa/TestFlight) and Android (.aab/Play Console)
• Clean, well-commented source code in a Git repo
• Short hand-off document outlining API keys, environment variables, and build steps

Acceptance criteria
1. Test card transaction registers successfully in the finance provider’s dashboard
2. No crashes on iOS 16+ and Android 12+ devices
3. Installs and runs through official beta channels without side-loading

Let me know the stack you recommend, any similar work you’ve shipped, and an estimated timeline so we can get this prototype into testers’ hands soon.