http://cloudmatch.io . A server-side app to enable cross-device gesture interaction. Imagine swiping pictures from one phone to another. Currently used by a game app: https://play.google.com/store/apps/details?id=perfectearth.a... . The engine of my server app is open-source and I tried to make some profit offering it as a cloud service - hence the name.

We use WebSockets :) WebRTC is definitely an option to consider!

Using websockets myself for my projects! Love the simplicity and speed.

Hey zillwc, thanks for trying the demo out. The requirements are an internet connection (any should do; WiFi, 3/4G etc) and the availability of Location Services.

There is a link to the github repos in the 'Get Started' section, where it says "The demo apps are open source and come with the respective development guide." Unfortunately only the Android version is there now. Will try to make it more visible!

link to github project: https://github.com/fabio2722/android-categorize-contacts