Video Call App Development

I'm looking for a developer to create an app similar to Popo with primary functionality being video calling. The app should be deployable on the Play Store and also compatible with iOS.

Key features:
- Video calling as the main function
- Group calls
- Screen sharing

Ideal candidate should have:
- Extensive experience in developing interactive video calling applications
- Proven track record of successful Play Store and iOS app deployment
- Strong understanding of group call and screen sharing functionality

Please provide examples of similar projects you've worked on in your proposal.