In an era characterized by digital transformation, WebRTC-based voice call apps have witnessed a surge in popularity due to technology advancements. These APIs serve as the essential bridges for companies to incorporate voice call functionality into their applications, facilitating connectivity and business transactions. To navigate the market, developers should consider four crucial criteria: variety in API features, popularity and market demand, cost and investment, and compatibility and ease of integration. The article presents a list of 10 best audio calling APIs & SDKs, including Video SDK, Twilio, MirrorFly, Agora, Sendbird, Plivo, Sinch, EnableX, Vonage, and MessageBird, highlighting their features, pros, and cons to help developers make informed decisions.