Secure Mobile Chat App

I’m ready to build a modern chat application that ships simultaneously on iOS and Android. The scope for this first release is focused and clear: fast, reliable text messaging backed by end-to-end encryption, with full emoji and sticker support to make conversations feel lively and personal.

Here is what I need delivered:
• One native-quality build for iOS and one for Android, both drawing from a single codebase if you prefer Flutter, React Native or a similar framework, or two fully native projects if that is your strength.
• A real-time messaging layer that keeps messages in sync across devices, even with intermittent connectivity.
• End-to-end encryption applied to every message, including attachments sent as emojis or stickers, so content is unreadable outside the chat.
• A lightweight, responsive UI that follows the latest Human Interface Guidelines and Material Design standards respectively.
• A small, self-maintainable admin panel or CLI script that lets me rotate encryption keys and manage basic user metrics.

Acceptance criteria
1. Both apps pass App Store and Google Play review in the TestFlight / internal testing phase.
2. Messages, emojis and stickers travel instantly between two test devices on different platforms without data leaks when inspected with network sniffers.
3. Source code is handed over, cleanly documented, with instructions to reproduce the release builds.

If you’ve shipped chat or real-time features before and have a preferred tech stack, let me know why it’s the right fit—I’m flexible on tooling so long as performance, security and maintainability stay front and centre.