The open-source telephony development world has been changing drastically over the last 2 years. Projects like FreeSWITCH allow you to create simple phone applications with XML files, but until recently, advanced applications required a solid knowledge of the Erlang language. Then enters Twilio— which allows any web developer to make advanced telephony apps in the web language of their choice. But with Twilio’s pricing structure, you are looking at anywhere from 2 to 4 cents per minute IN ADDITION to your VOIP service while also being locked-in to their cloud. Must I learn Erlang if I want to make cool telephony apps for free?