Flutter Developer

I need a polished productivity app that runs natively on both iOS and Android. The core purpose is to let small teams collaborate in real time—think shared workspaces, comment threads, and live file updates—so “Collaboration tools” sit at the heart of every screen flow.

The first release will focus on:
• User-friendly sign-up / sign-in (email, Apple, Google)
• A space where users can create, edit, and share items together with presence indicators
• Push and in-app notifications when a teammate adds or changes content
• Secure cloud sync so data is instantly mirrored across devices
• A lightweight admin panel (web or in-app) to manage users and permissions

I’m open to React Native, Flutter, or a comparable cross-platform stack as long as the final result feels fully native and meets App Store and Google Play guidelines. Clean, well-documented code and a short hand-off video are part of the hand-over.

Acceptance criteria
1. Both iOS and Android builds pass store reviews on first submission.
2. Real-time collaboration shows no more than a two-second latency on 4G.
3. Security audit (OWASP mobile top 10) returns no high-severity issues.

Please factor time for one design iteration after the interactive prototype.