Cross-Platform Productivity Mobile App Build

I already have a detailed project file that maps out the screens, user flow, and feature set for a productivity app, and I now need it turned into a working mobile application that runs smoothly on both iOS and Android. The goal is to translate the existing design and logic into clean, well-structured code, integrate any required APIs, and hand back polished builds ready for App Store and Google Play submission.

Because the app is productivity-focused, performance, offline resilience, and an intuitive user experience are critical. I’m flexible on the tech stack—Swift/ Kotlin, React Native, Flutter, or another modern cross-platform framework are all acceptable as long as the end result meets platform guidelines and can be maintained easily.

What I’ll hand over:
• The complete project file with screen designs, user stories, and feature priorities.
• Brand assets and a concise style guide.

What I need back:
• Fully functional iOS and Android apps compiled from the same codebase where possible.
• Source code stored in a private Git repo with clear commit history.
• A short README covering build/setup steps, third-party libraries, and environment variables.
• Assistance generating release builds and guidance on first-time store submission, including provisioning profiles and signing.

Acceptance criteria: both apps must match the designs pixel-for-pixel, pass standard UI/UX checks on current OS versions, and achieve zero critical crashes in TestFlight/Play internal testing.

If you have proven experience shipping productivity apps and can keep communication tight throughout the build, I’m ready to share the project file and kick off right away.