Cross-Platform Diagnostic App

I have a working Python script that already handles the core logic of decrypting, parsing, and responding to data coming from my consumer-electronics hardware. Now I need that logic turned into a polished, multi-page mobile application that runs smoothly on both Android and iOS and is eligible for the Google Play and Apple App Stores.

Core scope
The app must establish two-way communication over both USB serial (when a cable is connected) and the internet (Wi-Fi / cellular). It must request and verify location services, internet access, and a unique device identifier before enabling its diagnostic functions. As data arrives it has to be decrypted, parsed, and rendered in a clear interface that also lets me adjust settings on the target device and push updated firmware when required.

Essential diagnostic features
• Real-time data monitoring
• Data sending and receiving
• System updates

Technical expectations
– Translate or refactor the existing Python logic into the chosen mobile stack and wrap it in an intuitive, tab- or page-based GUI.
– Implement secure USB serial and socket communication layers, including automatic fallback from one transport to the other.
– Handle encryption/decryption exactly as the current script does, preserving packet structure and timing.
– Build, test, and package the app so it meets all Play Store and App Store submission requirements (entitlements, privacy disclosures, code-signing, etc.).
– Deliver the complete, well-commented source code and any build scripts so I can extend the project later; full ownership transfers to me on final payment.

Acceptance criteria
The compiled app must install on recent Android and iOS devices, connect to my hardware over both transports without timeouts, display the decoded values in real time, allow parameter changes that are confirmed by the hardware, and upload a small firmware file in under two minutes on a standard broadband connection.

If you have cross-platform mobile experience (Flutter, React Native, Kotlin + Swift, or similar) and are comfortable with low-level serial I/O, encryption, and App Store compliance, I’d love to see how you would approach this build and a rough timeline to first testable APK/IPA.