Android Social Chat App Development

I want to launch a clean, lightweight Android app whose sole purpose is real-time communication. Anyone should be able to download it, create an account in seconds, and start chatting—either one-on-one or in groups—without needing an invitation or admin approval.

Core experience
• Account creation: simple email, phone, or social sign-in so the barrier to entry stays low.
• Private messages: fast, reliable text exchange with read receipts and push notifications.
• Group chats: create, join, and leave rooms on the fly, with basic admin controls for the room creator.

Technical notes
I am leaning toward Kotlin in Android Studio with a cloud-hosted backend (Firebase Realtime Database/Firestore, Firebase Auth, and FCM are fine alternatives), but I’m open to other modern stacks that can scale and keep latency down. Security and data privacy matter, so please outline any encryption or compliance you plan to implement.

Deliverables
- Fully functional Android APK plus source code in a Git repo
- Brief setup documentation so I can run the project locally and deploy the backend
- One round of post-launch bug fixes included

Acceptance criteria
The build is considered complete when a new user can:
1. Register from a fresh install
2. Send and receive a direct message instantly
3. Create a group, invite others via link, and exchange messages in real time

Let me know your proposed tech stack, timeline, and any similar chat projects you’ve shipped.