In-House Team Chatting Tool Development

I need a talented developer to construct a robust in-house team chatting tool, with a design and functionality model similar to ones you might find in Teams or Slack.

Key Features Needed:
- Real-time messaging
- File sharing
- Group chat
- Unlimited users
- Unlimited channels/groups
- Private communication / 1:1 communication
- Unlimited chat history
- Searchable history
- Storage, max file size capacity = standard
- Data Security and privacy compliance
- Admin can send invitation to join platform
- Sign-up/Sign-in with Email id only

Platforms/Devices:
- Web-Based
- Desktop Application (Window and Mac - All versions)

Please note, there is no need for the tool to have any specific third-party integrations.

Ideal Skills and Experience:
- Demonstrated experience developing similar communication tools
- Familiarity with common chat tool features and functionalities
- Comfortable developing for both web and desktop platforms.

**** VERY IMP:
- Must sign NDA
- MUST SUBMIT ALL ORIGINAL PROGRAMS, CODES, FILES IN NATIVE FILE FORMAT AT THE END OF THE PROJECT