Our company Globetel Consultancy Service is based in Malaysia. We are looking for a candidate who can help to develop a SIP to viber/whatsapp gateway. The gateway should be able to convert the incoming voice calls over SIP and forward that through viber/whatsapp in order to complete the call to the receiver number. In addition to that it should be able to return the correct call error codes such as "Callee Busy", "Callee Unavailable", "Call connected Successfully" to the SIP backend. The candidate can choose any platform.