List of Free or Open source Softwares for VoIP

Here is the list of some of the most popular Free/Open source VoIP software phones.

BitWise IM :

OS : Linux, Mac OS X, Windows
Licence : Freeware / Closed Proprietary
Protocols compatible with :
Encryption : Blowfish
Feature : File transfer, whiteboard

BitWise IM is a secure, cross-platform instant messaging client written using wxWidgets and is available for Windows, Mac OS X and Linux. It comes in two flavors, Personal and Professional. The Personal version is free but limited to personal / home use; the Professional version provides private IM networks for corporate, non-profit and academic organizations


OS : Windows
Licence : Freeware / Closed Proprietary
Protocols compatible with :
Encryption : AES
Feature : Text chat, Video, File transfer, Whiteboard, Co-Browse, Voice mail, Voice conference

Brosix is a powerful, easy to use Instant Messenger suitable for enterprises and individuals that seek to improve communications, business productivity and relationships with partners and customers. Brosix rich set of features meets the increasing business demand for secure Instant Messaging and collaboration.

Coccinella :

OS : FreeBSD, Linux, Mac OS X, Windows
Licence : GPL Free software
Protocols compatible with : XMPP, Jabber, IAX
Encryption : Supports TLS/SSL and SASL
Feature : File transfer, whiteboard

It is a free software client for the Jabber/XMPP instant messaging protocol. It is written in Tcl/Tk, and runs on a range of platforms, including GNU/Linux, BSD, Solaris and Windows.

CounterPath X-Lite :

OS : Windows, Mac, Linux
Licence : Freeware
Protocols compatible with : SIP, STUN, ICE
Encryption :
Feature : IM, single login account, for Windows and Mac also Conferencing, Video and SIMPLE based presence.

X-Lite is a proprietary freeware VoIP soft phone that uses the Session Initiation Protocol. X-Lite is developed by CounterPath. X-Lite supports SRTP and soon ZRTP.
There are currently two major releases of X-Lite with radically different interfaces. X-Lite 2.0 for Mac and Linux, which uses the old X-Pro code base, and X-Lite 3.0 for Windows which uses the eyeBeam code base. X-Lite 2.0 is audio only. X-Lite 3.0 has audio, video, and instant messaging as well as being presence-capable.

Ekiga :

OS : Linux, Windows
Licence : GPL Free software
Protocols compatible with : SIP, H.323, STUN, Zeroconf
Encryption :
Feature : Video, IM

Ekiga is an H.323 compatible videoconferencing and VOIP/IP-Telephony application that allows you to make audio and video calls to remote users with H.323 hardware or software (such as Microsoft Netmeeting). It supports all modern videoconferencing features, such as registering to an ILS directory, gatekeeper support, making multi-user conference calls using an external MCU, using modern Quicknet telephony cards, and making PC-To-Phone calls.
Ekiga was previously known as GnomeMeeting.

Fring :

OS : Nokia S60 2nd and 3rd Edition
Licence : Freeware
Protocols compatible with : SIP, Proprietary protocol
Encryption :
Feature : Free mobile VoIP, Skype, SkypeOut, MSN, Google Talk, GSM, IM, 3G, GPRS, Wi-Fi, PC to phone, Phone to PC.

Fring is a free mobile VoIP software that lets you talk and live chat (IM) using your handset's Internet connection instead of costly mobile airtime (GSM) minutes. fring enables free mobile calls over Wi-Fi Internet access or your GPRS, EDGE or 3G Internet data plan.
fring lets you easily communicate with all your fring, Skype®, MSN® Messenger, Google Talk™ , Twitter and regular phone contacts from one, integrated contact list.

Gizmo :

OS : Linux, Mac OS X, Windows XP/2000
Licence : Freeware
Protocols compatible with : SIP, XMPP, Jabber
Encryption : SRTP
Feature : Recording, voicemail, Jabber IM, Gizmo to phone, phone to Gizmo, Talk with Yahoo! Messenger, Google Talk, or Windows Live user.

Gizmo unlike its competitor network Skype, the Gizmo Project network uses open standards for call management, the Session Initiation Protocol and Jabber.[2] But it uses several proprietary codecs, and like Skype the Gizmo Project client is proprietary/closed source software. The Gizmo Project is run by the company SIPphone.

Google Talk :

OS : Windows XP/2000
Licence : Freeware (libjingle is Free software)
Protocols compatible with : XMPP, Jabber
Encryption :
Feature : Chat, file transfer, voicemail, mail via "GMail Integration"

The Google Talk client is currently only available for Windows (2000, XP, Server 2003, and Vista), but with the release of the Google Talk gadget, a user on any operating system with a web browser can use Google Talk. However, other XMPP clients, such as Pidgin, fully support other operating systems.
Instant messaging between the Google Talk servers and its clients uses an open protocol, XMPP, allowing users of other XMPP clients to communicate with Google Talk users. VoIP in Google Talk is based around the Jingle protocol. The technology used within the Google server network however is not publicly known.

Jabbin :

OS : Linux, Windows
Licence : GPL Free software
Protocols compatible with : Libjingle, XMPP, Jabber
Encryption : SSL
Feature : Instant messaging, file transfer, compatible with Google Talk.

Jabbin is an open source Jabber client program that allows free PC to PC calls using VoIP over the Jabber network.

KPhone :

OS : Linux (KDE)
Licence : GPL Free software
Protocols compatible with : SIP, STUN, NAPTR/SRV
Encryption : SRTP
Feature : Video, voice, IM, external Sessions, IPv6 support for UDP

KPhone is a SIP User Agent for Linux. It implements the functionality of a VoIP Softphone but is not restricted to this. KPhone is licensed under the GNU General Public License. KPhone is written in C++ and uses Qt.

linphone :

OS : Linux and Microsoft Windows
Licence : Free software and open source
Protocols compatible with : SIP
Encryption :
Feature : Video, IM, STUN, IPv6

linphone is a SIP webphone with support for several different codecs, including speex.
Linphone is a web phone: it let you phone to your friends anywhere in the whole world, freely, simply by using the internet. The cost of the phone call is the cost that you spend connected to the internet.
linphone features include:

  • Works with the Gnome Desktop under Linux, (maybe others Unixes as well, but this has never been tested). Nevertheless you can use linphone under KDE, of course!
  • Since version 0.9.0, linphone can be compiled and used without gnome, in console mode, by using the program called "linphonec" .
  • Works as simply as a cellular phone. Two buttons, no more.
  • Linphones includes a large variety of codecs (G711-ulaw, G711-alaw, LPC10-15, GSM, and SPEEX). Thanks to the Speex codec it is able to provide high quality talks even with slow internet connections, like 28k modems.
  • Understands the SIP protocol. SIP is a standardised protocol from the IETF, that is the organisation that made most of the protocols used in the Internet. This guaranties compatibility with most SIP - compatible web phones.

Microsoft NetMeeting :

OS : Windows
Licence : Freeware
Protocols compatible with : h.323
Encryption :
Feature :

NetMeeting is Microsoft's free H.323-compliant VoIP software phone for Windows.

minisip :

OS : Windows XP, 2000, Linux, Windows Mobile
Licence : GPL / LGPL Free software
Protocols compatible with : SIP
Encryption : SRTP, TLS, MIKEY (DH, PSK, PKE), end to end encryption
Feature : Video, IM Conferencing

minisip is a SIP VoIP soft phone that implements additional security features such as mutual authentication, encryption and integrity of on-going calls, and encryption of the signaling (SIP over TLS). These security features use work-in-progress IETF standards (SRTP and MIKEY).

OpenH323 Project :

OS : Linux, Mac OS X, Windows, Windows Mobile, VxWorks
Licence : MPL free software
Protocols compatible with : H.323, SIP, IAX, RTP, STUN
Encryption : SRTP
Feature :

The OpenH323 project aims to create a full featured, interoperable implementation of the ITU-T H.323 teleconferencing protocol that can be used by personal developers and by commercial users without charge.

Phoner and Phonet Lite :

OS : Windows
Licence : Freeware
Protocols compatible with : SIP, CAPI
Encryption : TLS, SRTP
Feature : recording, voicemail

Phoner is a Windows application for PC based telephony - a so called softphone. This freeware tool supports ISDN hardware that offers CAPI and all kinds of telephony equipment that supports TAPI. SIP is implemented for enabling calls over computer networks like the internet. There is a special version supporting SIP only with some less features: PhonerLite.

reSIProcate :

OS : Linux, Mac OS X, Windows
Licence : Vovida Software License (open source)
Protocols compatible with : SIP
Encryption : TLS, Identity, Digest-Authentication
Feature : SIP Stack, Dialog layer (DUM), Proxy (repro)

The reSIProcate project is part of the SIPfoundry community. The project aims at building a freely available, completely standards based and complete reference implementation of a SIP stack including an easy to use application layer API. The reSIProcate stack is currently used in several commercial products and is very stable.

SightSpeed :

OS : Mac OS X / Windows
Licence : Freeware
Protocols compatible with : SIP,RTP,Proprietary P2P protocol
Encryption :
Feature : video, voicemail, phone in, phone out, multiparty calling, conference recording, text messaging, interop with hardware SIP phones, nat traversal, video mail

SightSpeed is a videoconferencing, VoIP and instant messaging client for Microsoft Windows and Apple Macintosh operating systems. The service allows people to make video calls, computer-to-computer voice calls, and calls to regular telephones, with free and paid versions.

SIPSet :

OS : Linux
Licence : GPL / LGPL Free software
Protocols compatible with : SIP
Encryption :
Feature : Video, Ip6, NAT

SIPSet is a SIP User Agent with a GUI front end that works with the Vovida SIP stack. You can use the SIPSet as a soft phone, to make and receives phone calls from your Linux PC.
The current release of SIPSet implements these features and functionality:

  • SIPSet can make calls through a SIP proxy.
  • SIPSet can register to receive calls through a SIP proxy.
  • SIPSet can make and receive calls directly with another User Agent.

SJphone :

OS : Windows 2000/Windows XP, Windows Vista, Mac OS X, Linux, Windows Mobile 5
Licence : Freeware
Protocols compatible with : SIP, RTP, STUN, Jabber, H.323
Encryption : Customisation for ITSP

SJphone is a VoIP softphone. This software allows you to speak with any other SIP softphones running on a PC or PDA, any stand-alone IP-phone, or using ITSP (Internet Telephony Service Provider) with any traditional wired or mobile phone. It supports both the SIP and H.323 standard sets, NAT traversal, and works with most major ITSP like Free World Dialup, and IP-PBX and VoIP gateway vendors. SJphone is available for personal computers with MS Windows XP/Vista, MAC OS X and Linux. SJphone also works on most wireless PDAs or communicators like HP Ipaq, Fujitsu-Siemens PocketLOOX, Symbol, and many others.

Skype :

OS : Windows 2000/XP, Mac OS X, Linux, Pocket PC
Licence : Freeware
Protocols compatible with : Proprietary P2P protocol
Encryption : Encrypted
Feature : Video (not on Linux yet), file transfer, voicemail, Skype to phone, phone to Skype, additional P2P extensions (games, whiteboard, etc...)

Skype is a peer-to-peer Internet telephony. It competes against existing open VoIP protocols such as SIP, IAX, and H.323. Skype has experienced rapid growth in both popular usage and software development since launch, both of its free and its paid services. The Skype communications system is notable for its broad range of features, including free voice and video conferencing, its ability to use peer to peer (decentralized) technology to overcome common firewall and NAT (Network address translation) problems, its use of transparent, strong encryption and its extreme[2] countermeasures against reverse engineering of the software or protocol.

SpeakFreely :

OS : Windows XP/2000/NT/98
Licence : GPL free software
Protocols compatible with : RTP protocol
Encryption : DES, IDEA
Feature :

Speak Freely is a 100% free Internet telephone originally written in 1991 by John Walker, founder of Autodesk. After April of 1996, he discontinued development on the program. Since then, several other Internet "telephones" have cropped up all over the world. However, most of these programs cost money. Most of them have poor sound quality, and don't support Speak Freely's basic features such as encryption, the answering machine, or selectable compression.

Twinkle :

OS : Linux
Licence : GPL free software
Protocols compatible with : SIP
Encryption : SRTP, ZRTP
Feature :

Twinkle is a soft phone for VoIP communcations using the SIP protocol. You can use Twinkle for direct IP phone to IP phone communications or in a network using a SIP proxy to route your calls.
In addition to making basic voice calls, Twinkle also provides the following features:

  • 2 call appearances (lines)
  • Multiple active call identities
  • Custom ring tones
  • Call Waiting
  • Call Hold
  • 3-way conference calling
  • Mute
  • Call redirection on demand
  • Call redirection unconditional
  • Call redirection when busy
  • Call redirection no answer
  • Reject call redirection request
  • Blind call transfer
  • Reject call transfer request
  • Call reject
  • Repeat last call
  • Do not disturb
  • Auto answer
  • User defineable scripts triggered on call events
  • E.g. to implement selective call reject or distinctive ringing
  • RFC 2833 DTMF events
  • Inband DTMF
  • Out-of-band DTMF (SIP INFO)
  • STUN support for NAT traversal
  • Send NAT keep alive packets when using STUN
  • NAT traversal through static provisioning
  • Missed call indication
  • History of call detail records for incoming, outgoing, successful and missed calls
  • DNS SRV support

WengoPhone :

OS : Linux, Mac OS X, Windows XP/2000, SmartPhone, Windows Mobile
Licence : GPL free software
Protocols compatible with : SIP
Encryption :
Feature : Video, IM (Yahoo!, MSN, Jabber, GoogleTalk), voicemail, wengo to phone.

WengoPhone is a SIP phone which allows users to speak at no cost from one's computer to other users of SIP compliant VoIP software. It also allows users to call landlines, cellphones, send SMS messages and to make video calls. None of this functionality is tied to a particular SIP provider and can be used with any provider available on the market, unlike proprietary solutions such as Skype.

Windows Live Messenger :

OS : Windows 2000/XP/Vista
Licence : Freeware
Protocols compatible with : SIP, RTP, proprietary
Encryption :
Feature : Video, voice, chat, text messaging, PC to Phone

Windows Live Messenger (WLM), still commonly referred to by the previous name of MSN Messenger (MSN for short), is an instant messaging client for Windows XP, Windows Server 2003, Windows Vista, and Windows Mobile. In addition to PC-to-PC calls, Windows Live Messenger now supports PC-to-phone calls with Windows Live Call.

wxCommunicator :

OS : Windows XP/2000
Licence : GPL free software
Protocols compatible with : software SIP, STUN, TURN, ICE,
Encryption :
Feature : Voice, chat, recording, conferencing, multiple sip profiles

wxCommunicator is an open source SIP softphone released under GNU GPL version 2 licence. It is based on sipXtapi client library and wxWidgets 2.8.4 GUI library. It allows users to make phone calls to other users via SIP and chat. GUI relies entirely on wxWidgets XRC resource system.

Yahoo! Messenger :

OS : Microsoft Windows, Mac OS (8, 9, X), (Linux/FreeBSD version not VoIP capable)
Licence : Freeware
Protocols compatible with : SIP (using TLS) and RTP (media)
Encryption : Video, file transfer, PC to phone, phone to PC

Yahoo!. Yahoo! Voice is a Voice over IP PC-PC, PC-Phone and Phone-to-PC service provided by Yahoo! via its Yahoo! Messenger instant messaging application.

For more Comprehensive list of software check out :

Some of the worth mentioning services from Skype : (Not Free but worth it)

SkypeOut : lets you call landlines and mobile phones around the world at local rates and users can buy credit in units of €10 or €25.

SkypeIn : gives you a personal number so that friends can call you on Skype from their old-fashioned phones, wherever you connect around the world. A SkypeIn number costs €10 for 3 months or €30 for a full year and comes with free Skype Voicemail.

Skype Voicemail : lets you pickup messages when you’re offline, away from your computer… or just ignoring people. A Skype Voicemail subscription costs €5 for 3 months or €15 for a year.