Voice API is referred to as a tool that allows software developers to integrate calling features using an Application Programming Interface (API). Developers build a chat app with voice functionality and Voice APIs let these apps make and receive phone calls acting as a bridge to PSTN (Public Switched Telephone Network).
These voice APIs are highly flexible for developers as they simplify the app's design and development by saving money and time. APIs are considered to be the most simplified way to connect any infrastructure through cloud-native app development, wherein they also permit the developers to share their data with other external sources.