Professional Networking Mobile App Development

I'm looking to develop a professional networking mobile app. This app should primarily serve the purpose of connecting professionals across various industries.

Core Features:
- Messaging: A robust messaging system is crucial for this app. It should facilitate seamless communication among users.

Messaging Functionalities:
- Text Chat: Users should be able to send and receive text messages in real-time.
- Voice and Video Calls: The app should support voice and video calls, providing users with multiple modes of communication.
- File Sharing: Users should be able to share files with each other, making the app a useful tool for professional collaboration.

Ideal Skills and Experience:
- Proven experience in mobile app development, particularly social networking apps.
- Expertise in integrating messaging functionalities within an app.
- Familiarity with platforms for professional networking.
- Strong understanding of user interface and user experience design principles to ensure the app is easy to use and visually appealing.