Comprehensive VoIP Messaging and Calling App

I'm looking for a skilled Android developer to create a fully functional VoIP app. This app should include:

- Text messaging
- Voice calling
- Video calling
- Picture messaging

The app must also support:

- Video messaging
- Real phone numbers exclusively in Canada and the USA
- Login via email and password
- Contact saving

Ideal candidates for this project will have a strong background in developing VoIP applications, particularly for the Android platform. Experience with integrating real phone number functionalities and contact saving features will be considered an asset. Please provide examples of prior VoIP projects in your proposal.