FreeSWITCH
FreeSWITCH is an open-source telephony platform designed for building voice, video, and messaging applications. It functions as a softswitch, handling call routing, media processing, and protocol translation for VoIP (Voice over IP) systems. It supports a wide range of telephony protocols and is highly scalable, making it suitable for everything from small PBX systems to large carrier deployments.
Developers should learn FreeSWITCH when building real-time communication applications like call centers, IVR (Interactive Voice Response) systems, conferencing solutions, or SIP trunking services. It's particularly valuable for projects requiring custom telephony logic, multi-protocol support (e.g., SIP, WebRTC), or high-performance media handling, as it offers flexibility through its modular architecture and scripting capabilities in languages like Lua.