We have selected the best five open-source SIP libraries ranking-wise, and our criteria to rank the best five applications are based on Github Github project stars + update frequency + latest development and maturity of the application in question. However, we are not rigid on it and open to accept any feedback from user personal experience.

Sofia-SIP

Sofia SIP is also an open-source SIPsupported library. It is also called the SIP user-agent library. It is based on the IETF RFC3261 specification and is used for communication like person to person, instant messaging (IM), Voice over Internet Protocol (VoIP), and real-time communication. It is also used for making SIP client software. Nokia Research Center (NRK) has developed the SIP stack. Sofia-Sip is based on the SIP Stack. It supports both UDP and TCP. Sofia-SIP includes features of early media, sessions, session timers, provisional response, caller preferences, etc.

Osip

Osip is an LGPL implementation of SIP. It's stable, portable, flexible, and compliant! -maybe more-! It is used mostly with the eXosip2 stack (GPL) which provides a simpler API for User-agent implementation.

SIP.js

SIP.js is a simple, intuitive, and powerful JavaScript signaling library. It is a full-featured SIP stack written in JavaScript. With SIP.js, you can harness the power of WebRTC to build audio, video, and real-time data into your application. SIP.js is fast, lightweight, and easy to use.

JsSIP

JsSIP is a simple-to-use JavaScript library that leverages the latest developments in SIP and WebRTC to provide a fully-featured SIP endpoint on any website. With JsSIP, any website can get Real-Time Communications features using audio, video, and more with just a few lines of code.

Features

• SIP over WebSocket transport.
• Audio/video calls, instant messaging, and presence.
• Lightweight!
• 100% pure JavaScript built from the ground up.
• Easy to use and powerful user API.
• Works with OverSIP, Kamailio, and Asterisk servers.

PJSIP

PJSIP is a free and open-source multimedia communication library written in C language implementing standard-based protocols such as SIP, SDP, RTP, STUN, TURN, and ICE. It combines signaling protocol (SIP) with a rich multimedia framework and NAT traversal functionality into a high-level API that is portable and suitable for almost any type of system ranging from desktops, embedded systems, to mobile handsets.

PJSIP is both compact and feature-rich, supporting audio, video, presence, and instant messaging. It has extensive documentation and is very portable. On mobile devices, it abstracts system-dependent features and in many cases is able to utilize the native multimedia capabilities of the device.

PJSIP has been developed by a small team working exclusively for the project since 2005, with the participation of hundreds of developers from around the world, and is routinely tested at SIP Interoperability Event (SIPit) since 2007. Here is a list of projects developed over PJSIP Open Source Projects based on PJSIP.

Conclusion

In conclusion, the realm of open-source SIP libraries offers a diverse set of options for developers seeking to integrate Session Initiation Protocol functionality into their applications. Each library brings its strengths to the table, catering to various project requirements and preferences.

From the comprehensive multimedia capabilities of PJSIP to the lightweight and modular design of Sofia-SIP, the open-source landscape provides solutions for different use cases. reSIProcate emphasizes scalability and security, Linphone offers a user-friendly approach with cross-platform support, and SipWise NGCP targets service providers with carrier-grade features.

ICT Innovations is an open-source telephony service provider. Contact Us for deployment and development of open-source telephony projects.