In-app voice calling refers to the capability of making and receiving phone calls directly from within a mobile application. This eliminates the reliance on external communication platforms like traditional phone networks or third-party calling apps. In-app voice calling is commonly used in various contexts, such as customer support, collaboration tools, social networking apps, and on-demand service apps. These multiple use cases are driving the success of the Voice over Internet Protocol (VoIP) industry, which is expected to grow to $102.5 billion by 2026