I want to create an app similer to whatsapp.
1. p2p chat functionality
2. create group functionality
3. forword massage.
4. audio and vedio call.
5. sync contact.
6. send file and document by app in chat.
7. send invitations
I want to build this app in react native for android and ios.
Please submit your minimum budget and time estimate.
Please also explain how you process this step by step.