SIP SIMPLE client SDK is a Software Development Kit for easy development of SIP multimedia end-points with features beyond VoIP like Video, Chat, File Transfers, Screen Sharing and Presence. Other media types can be easily added by using an extensible high-level API.
The software LICENSE is GPL v3. If you need an alternative license contact AG Projects.


SIP stands for 'Session Initiation Protocol', an IETF standard described by RFC 3261. SIP is an Internet application-layer control protocol that can establish, modify and terminate multimedia sessions such as Internet telephony calls (VoIP). Media can be added to (and removed from) an existing session.

Sip simple components

SIP allows the endpoints to negotiate and combine any type of session they mutually understand like Audio, Video, Instant Messaging (IM), File Transfer, Desktop Sharing and provides a generic event notification system with real-time Publications and Subscriptions about state changes that can be used for asynchronous services like Presence, Message Waiting Indicator and Busy Line Appearance.


The SDK has cross platform capabilities on Linux OS, Mac OSX and Microsoft Windows. The library should work with minimal changes on any platform that supports C and Python development environments.

  • Sip Clients - SIP Command Line Tools

  • Blink - SIP Client for Mac, Linux and Windows

  • SylkServer - SIP Application server (Multiparty Conferencing, XMPP and IRC gateway)

For the complete list of features check the Features and Standards page.