mesibo

[derin]

Mesibo Messenger is an open-source app with real-time messaging, voice, and video call features. We have released the entire source code of Mesibo Android, iOS, and JavaScript Apps on GitHub, where it can be continuously updated. You can download the entire source code, customize, and reuse in your own mesibo based applications without any restrictions.
Features

One-on-one messaging and Group chat
High quality voice and video calling
Rich messaging (text, picture, video, audio, other files)
Encryption
Location sharing
Message status and typing indicators
Online status (presence) and real-time profile update
Push notifications

Host it anywhere - in your private data cneter, Amazon aws, Google Cloud, Microsoft Azure, Alibaba cloud, etc. You can even run it alongside your webserver. Mesibo On-Premise platform is distributed as a docker image so that you can run it on almost all the hosting providers.

https://mesibo.com/on-premise/

[robi]

Docs of source code locations on Github.
https://mesibo.com/documentation/source-code/