VoIP (Voice Over IP)

Voice Over Internet Protocol (VoIP) is a category of hardware and software that enables voice calls to be made and received over the internet.

VoIP allows users to send and receive voice calls over the internet, without the need for traditional telephones or circuit transmission. Instead, VoIP sends voice data as data packets that are delivered over a packet-switched network with media delivery protocols that allow callers to speak and listen as if they were talking over a PSTN connection.

VoIP is particularly popular in contact centers for its cheaper price point and tight integration capabilities with CRM systems. Although special VoIP-enabled desktop “hard” phones have been used in contact centers for many years, most contact centers now simply use a headset equipped with a microphone to connect the agent and caller. This is known as a “soft” phone.

VoIP also has functionality advantages over conventional telephony. Incoming calls can be easily routed to a VoIP phone, no matter where in the network it is physically plugged in, allowing “phones” to be anywhere with a stable internet connection. Calls can be routed in concert with any number of digital protocols, and contact center agents can work remotely from anywhere using a VoIP phone. This makes call center scalability a much more practical reality than with conventional telephony alone.


The Twilio Programmable Voice SDKs give developers the ability to build a VoIP system that connects to any endpoint they choose, whether it is a desktop browser or a mobile app. Developers can also use Voice Insights to diagnose network and device problems and respond to them during a live call.