I am serving as a Team Lead in iOS and Mac OSx team, in a renowned IP Telephony company. I have develop apps that is used by millions now. My responsibility was to analyze feasibility, design and develop software on the field of mobile VoIP. I will customize and re brand open source VoIP app like line phone, idoubs pjsip for you which will work both in LAN and internet.I have expertise on developing demanding Video Call and Messaging feature with this kind of app too. Also I am ready to add feature such as audio call conference and video call conference. Can help you with server side troubleshooting on these kind of project. So confidently Invite me for this kind of projects.