PJSIP
PJSIP is an open-source multimedia communication library written in C, implementing protocols like SIP, SDP, RTP, STUN, TURN, and ICE to build VoIP and video conferencing applications. It provides a comprehensive API for handling signaling, media transport, and NAT traversal, supporting platforms including Windows, Linux, macOS, iOS, and Android. The library is designed for high performance and scalability, making it suitable for embedded systems, softphones, and enterprise communication solutions.
Developers should learn PJSIP when building real-time communication applications such as VoIP clients, video conferencing tools, or IoT devices requiring SIP-based communication, as it offers robust protocol support and cross-platform compatibility. It is particularly useful for projects needing low-level control over media handling and signaling, or when integrating with existing SIP infrastructure in enterprise or telecom environments.