Hi,
I have done 3 chat applications for mobile,web, and desktop ( windows). Also video chat too.
But for video chat the price may be little more. But first I need to know what exactly you want, how you want it to function, basically a detailed requirements.
This will help me to provide you a better price and timeline. I am sure me and my team can deliver the whatever you want but to satisfy your need we need to know your requirements.
Thanks and Regards,
Shankar