Agile Infoways has developed chat application on Android using Firebase.

The application is having below functionality:
1. One to One chat
2. Group Chat
3. Audio Call
4. Video Call
5. Multimedia Sharing
6. Audio Recording and Sharing
7. Stickers and GIF support
8. Block/Unblock User
9. Reply
10. Forward
11. App Invite
12. Chat background customization
13. Font customization
14. Enter to Send message
15. Location Sharing
16. Profile Info
17. Media reports of group and one to one chat
18. Call details

https://www.agileinfoways.com/inquiry/
Kindly contact us if you would like to develop similar application.