Spika is messenger module for Web/iOS/Android with backend system.
For detail plase see http://spikaapp.com/.
Insturaction for each device you can see here.
Backend
https://github.com/cloverstudio/Spika/tree/master/web/src/server
Web Client
https://github.com/cloverstudio/Spika/tree/master/web/src/client