Apps with 'SIP' feature
Jitsi (previously SIP Communicator) is an audio/video and chat communicator with full encryption that supports protocols such as SIP, XMPP/Jabber, ICQ/AIM, Windows Live, Yahoo!
Voice, video and chat communications, secure, decentralized, strong privacy and freedoms.
Linphone is an internet phone or Voice Over IP phone (VoIP). With Linphone you can communicate freely with people over the internet, with voice, video, and text instant messaging.
Zoiper IAX & SIP multilanguage and multiplatform (Windows, Linux and Mac OS X) softphone is a VoIP soft client, meant to work with any IP-based communications systems and...
Asterisk is free software that transforms a computer into a communication server. Asterisk lets you build applications like PBX, VoIP gateway, IVR and ACD.
MicroSIP is a free portable SIP softphone for Windows based on PJSIP stack.
FreePBX is a web-based open source GUI (graphical user interface) that controls and manages Asterisk (PBX), an open source communication server.
Wazo is a unified communications platform based on Asterisk and focused on extensibility.
Blink, a state of the art, easy to use SIP client. You can use it with any SIP provider or its own fully-featured SIP service. Voice over IP * HD Audio (G722/Speex)
3CX is a software-based, open standards IP PBX that offers complete Unified Communications, out of the box.
Thoughtfully designed, Bria 5 leverages over 10 years of softphone experience in improving productivity for our customers.
Kamailio® (successor of former OpenSER and SER) is an open source SIP server released under GPL, able to handle thousands of call setups per second.No screenshots yet
Potential Malware. Check comments.
QIP Infium is a multiprotocol instant messaging client. It supports ICQ (OSCAR), Jabber (XMPP), Mail.ru Agnet (MRA), IRC, XIMSS, SIP, Twitter, Facebook and other.
Lightweight portable SIP softphone with BLF and customizable keypad built with libre/librem/baresip BSD-licensed stack.
Softphone for VoIP, CAPI und TAPI.