Comparison of VoIP software

This is a comparison of voice over IP (VoIP) software used to conduct telephone-like voice conversations across Internet Protocol (IP) based networks. For residential markets, voice over IP phone service is often cheaper than traditional public switched telephone network (PSTN) service and can remove geographic restrictions to telephone numbers, e.g., have a PSTN phone number in a New York area code ring in Tokyo.

For businesses, VoIP obviates separate voice and data pipelines, channelling both types of traffic through the IP network while giving the telephony user a range of advanced abilities.

Softphones are client devices for making and receiving voice and video calls over the IP network with the standard functions of most original telephones and usually allow integration with VoIP phones and USB phones instead of using a computer's microphone and speakers (or headset). Most softphone clients run on the open Session Initiation Protocol (SIP) supporting various codecs. Skype runs on a closed proprietary networking protocol but additional business telephone system (PBX) software can allow a SIP based telephone system to connect to the Skype network.[1] Online chat programs now also incorporate voice and video communications.

Other VoIP software applications include conferencing servers, intercom systems, virtual foreign exchange services (FXOs) and adapted telephony software which concurrently support VoIP and public switched telephone network (PSTN) like Interactive Voice Response (IVR) systems, dial in dictation, on hold and call recording servers.

Some entries below are Web-based VoIP; most are standalone Desktop applications.

Desktop applications

Program Operating systems License Costs Protocols Codecs Encryption Max conference peers Other abilities Latest release
AudioCodes MobilityPLUS Windows, Android, iOS Proprietary ? SIP, RTP, XMPP, STUN, ICE G.722 wideband, G.711a, G.711u, iLBC, G.729a, SILK, GSM, VP8, H.264, Opus TLS, SRTP Un­known Voice, video, IM, Group chat, content sharing, SMS and MMS over IP services, native and social network contacts integration, incoming call/IM push notifications. 2014 (2014)
Avaya Application Server 5300 Soft Client Windows Proprietary ? SIP, RTP Un­known TLS, SRTP Un­known 2.0; 2010 (2010)
Blink Linux, macOS, Windows Mixed: free software versions under GNU GPLv3 + shareware versions under gplv3 with exception of including proprietary code macOS version proprietary on App Store, free version limited to sponsored SIP provider; Windows version proprietary; Linux version open source ICE, SIP, MSRP, RFB (VNC), XCAP Opus, speex, G.722, GSM, iLBC, PCMU, PCMA TLS, SRTP and ZRTP on all versions, OTR/SMP on Linux and macOS only[2] No limit IM, file transfer, desktop sharing, multi-party conference, wideband Blink Qt
CSipSimple Android GPL Free SIP, ICE, STUN, TURN Opus, AMR, G.711 (u-law/a-law), speex, G.722, GSM, iLBC, G.729 (need to buy a licensed plugin), iSAC, SILK (narrow-band/wide-band/ultra wide-band) SRTP, SIP over TLS 1.0 and ZRTP Un­known SIP SIMPLE messaging, Support for IPv6, Integration with Android operating system with filters and rewriting rules 1.0.2; November 2014 (2014-11)
Cisco IP Communicator[3] Windows Proprietary Free (for Cisco SMB Partners only) SCCP (Skinny), SIP, TFTP, HTTP (for XML Services) G.722 wideband, G.711a, G.711u, iLBC, iSAC, G.729a, G.729ab SRTP No limit (with bridge), 2 otherwise[4] Call Recording, Silent Monitoring, Multiple lines and directory numbers, Configurable speed dial, Calling name and number display, Call Waiting, Call Forward, Call Transfer, Three-Way Calling (conference), Call Park, Call Pickup, Redial, Hold, Barge, Callback, Extension Mobility, Message waiting indicator, iDivert, Meet Me conferencing, Group Pickup, Do Not Disturb, XML Services 8.6.6; April 27, 2016 (2016-04-27)
CounterPath Corporation Bria Windows, macOS, iOS, Android Proprietary ? SIP, RTP, XMPP, STUN, ICE G.722 wideband, G.711a, G.711u, iLBC, G.729a, SILK, GSM, VP8, H.264, Opus TLS, SRTP 6 party voice, 3 party video Voice and video calling, SIP and XMPP messaging support, group chat, file, image and document sharing, contact integration, incoming call/IM push notifications 5.3.4 July 23, 2018 (2018-07-23)
Discord macOS, Android, iOS, Windows, Linux Proprietary Free, Premium "Nitro" Subscription for Additional Features. RTP, UDP, WS, HTTPS Opus TLS 5000 soft limit for voice calls,[5] 25 hard limit for video[6] IM, file sharing, in-game overlay 59746; April 24, 2020 (2020-04-24)
Ekiga Linux, Windows, OpenSolaris GPL Free SIP, H.323, STUN, Zeroconf, XMPP, RTP H.263, H.264/MPEG-4 AVC, Theora, iLBC, Speex, SILK, GSM, ... No Un­known Video, IM, LDAP, Call Forwarding, Call Transfer, Auto-answering, PC to phone, phone to PC, Multiple accounts, USP support, Message waiting indicator, SIMPLE-based presence etc. 4.0.1 (February 21, 2013 (2013-02-21)) [±][7]
Empathy Linux GPL Free SIP, XMPP (Jingle), ICE (STUN-TURN), Zeroconf Un­known No Un­known IM, multi-user A/V,[8] collaborative applications 3.12.12[9] (May 13, 2016 (2016-05-13)) [±]
Eyeball Chat Windows Proprietary Free SIP, STUN, ICE, XMPP Un­known Yes 5[10] IM, Conferencing, Voice, Video and SIMPLE based presence Windows 3.2; 2009 (2009)
eyeBeam Windows Proprietary ? SIP-SIMPLE Un­known TLS, SRTP 6 party audio; 3 party video Voice and Video calling; IM; Import Microsoft Outlook Contacts; USB Support; Call Recording and Conferencing 1.5.20.1; March 2010 (2010-03)
FaceTime iOS, macOS Proprietary Free SIP, IETF, Signaling protocol for VoIP, STUN, TURN and ICE| IETF, technologies for traversing firewalls and NAT H.264 Video, AAC-ELD Audio, H.263 and VP8 RTP, SRTP IETF|standards for delivering real-time and encrypted media streams for VoIP. 20 Video, voice, conferencing, with additional tools available as "Services".
Google Hangouts Linux, Windows, macOS, Android, iOS Proprietary (using libjingle) Free XMPP H.264/SVC, H.264/AVC, H.263 and VP8 SRTP 10 Video, chat, screen sharing, with additional tools available as "Hangout Apps". Google Chrome Web Store extension
2020.803.419.1 (August 12, 2020 (2020-08-12)) [±] [11]
IBM Sametime Linux, macOS, Windows, mobile Proprietary ? SIP-SIMPLE, T.120 H.323 TLS Un­known IM, File transfer, Voice, Presence, Server stored contact list, HTTP tunneling, plugins, embedable in Lotus Notes[12] 8.5.2; May 8, 2011 (2011-05-08)
Jami by Savoir-faire Linux Android, FreeBSD, iOS, iPhone, Linux, Microsoft Windows, OS X[13] GPL Free SIP, RTP, STUN per account, SRV, DHT, P2P Audio: Opus, Speex, G.722, G.711, GSM, VP8, G.729, iLBC. Video: H.264, H.263, VP8, MPEG-4 Voice encryption (SRTP with SDES or ZRTP) and signaling encryption (TLS), multiple realms authentication mechanism No limit Blockchain ID-management, Gnome-KDE client, address book, multiple accounts, unlimited call number, call transfer, call hold-unhold, call recording, multi-way conferencing
iOS3.07 / December 11, 2020 (2020-12-11)[14]
Android20201222-01 / December 28, 2020 (2020-12-28)[15]
Windows202012101022 / December 10, 2020 (2020-12-10) [16]
macOS1.88 / December 23, 2020 (2020-12-23)[17]
Jitsi Linux, macOS, Windows (all java supported). Experimental Android builds are also available.[18] Apache Free SIP-SIMPLE, XMPP-Jingle STUN ICE, TURN SILK, G.722, Speex, Opus, G.711 (PCMU/PCMA), iLBC, GSM, G.729, H.264, H.263, VP8 ZRTP, SRTP, OTR, TLS Un­known Text messaging, audio-video telephony, IPv6 (often broken,[19] P2P not supported[20]), call recording, 64-bit 2.10 (build.5550) (February 5, 2017 (2017-02-05)) [±]
KPhone Linux (KDE) GPL Free SIP, STUN, NAPTR-SRV Un­known SRTP Un­known Video, voice, IM, external Sessions, IPv6 support for UDP 1.2 (November 2008)
Librestream Onsight Connect Windows, Android, iOS Proprietary ? SIP, RTP, STUN G.711, H.264, MPEG, and others TLS, SRTP Un­known Voice, video, conferencing, image sharing, incoming call/IM push notifications. February 27, 2018 (2018-02-27)
Linphone Linux, Windows, macOS, Android, iPhone, BlackBerry GPL v.3 Free SIP Speex, Opus, G711, GSM, G.722, VP8 (WebM), H263, MPEG4, Theora and H264 (plugin) TLS, SRTP, ZRTP Un­known Video, IM, STUN, IPv6 (disables IPv4 support when enabled, P2P, Secure Encrypion, User own Encryption via Provided API [https://gitlab.linphone.org/BC/public/linphone-desktop) 4.1.1; April 30, 2020 (2020-04-30), provides daily snapshots via http://www.linphone.org/snapshots
Messages macOS Proprietary Free, only macOS and iOS SIP AIM ICQ XMPP H263, H264 Un­known Un­known Integrated, PBX independent 7.0; July 25, 2012 (2012-07-25)
MicroSIP Windows GPL Free SIP, STUN, ICE, SIMPLE Speex, iLBC, GSM, G.711, G.722, G.729, SILK, Linear PCM TLS, SRTP Un­known Video, voice, IM and Presence 3.20.3 (2 November 2020 (2020-11-02)) [±][21]
Mirial Softphone (Mirial s.u.r.l.) Windows 2000-XP-2003-Vista-7 (including 64-bit versions), macOS (x86) Proprietary not free SIP, RTSP H.323 DTLS-SRTP Un­known H.264 Full-HD 1080p video rx/tx, Two independent lines supporting Call Control and 3-Party videoconference in Continuous Presence, G.722.1/C wideband audio, Call recording/export, DV/HDMI/Component capture, Presentation (H.239, RFC-4796), Encryption, Far End Camera Control, GPU accel (D3D and OpenGL) 7.0.24; May 26, 2010 (2010-05-26), discontinued
Mumble Linux, macOS, iOS, Windows, Android New BSD license Free ICE CELT, Speex, Opus TLS and OCB-AES128 No limit (limited only by server bandwidth and memory) Chat with (limited) embedded HTML, Automatic Gain Control, very low latency, Access Control Lists for user management, Customizable In-Game Overlay for OpenGL and DirectX, Directional Audio, Plugin Support, Nested Channels, Echo cancellation for headset free use, Global Public Server List, Logitech G15 support, Push-To-Talk and Voice-Activation 1.3.0; September 7, 2019 (2019-09-07)
Nymgo Windows, Android, iOS Proprietary Free SIP, RTP and RTCP Un­known Yes No limit Address Book integration, Call recording/export, Mute, On Hold, Caller ID definition 4.2.9; March 2013 (2013-03)
oovoo macOS, iOS, Windows, Android Proprietary Free SIP, RTP and RTCP Un­known Yes 12 Address Book integration, Call recording/export, Mute, On Hold, Caller ID definition 4.2.9; March 2013 (2013-03)
Phoner Windows Proprietary Free SIP, TAPI, CAPI G.711a, G.711u, G.722, G.726, G.729, GSM, iLBC, speex, Opus TLS, SRTP, ZRTP 8 Conferencing, call redirection, call recording 3.22 (25 October 2019 (2019-10-25)) [±][22]
PhonerLite Windows Proprietary Free SIP G.711a, G.711u, G.722, G.726, G.729, GSM, iLBC, speex, Opus TLS, SRTP, ZRTP 8 Conferencing, call redirection, call recording 2.85 (1 December 2020 (2020-12-01)) [±][23]
QuteCom Linux, macOS, Windows XP-2000 GPL Free SIP G.711, G.729, iLBC, AMR-NB, G.722, Speex, AMR-WB (G.722.2), H.263, H.263+, H.264, Dirac[24] SRTP, but key exchange via Everbee key Exchange which is not a Standard Un­known Video, IM (MSN, AIM, ICQ, Yahoo!, XMPP, Google Talk), voicemail, wengo to phone, conferencing. 2.2.1 (22 June 2011 (2011-06-22)[25]) [±]
Roger Wilco GameSpy Windows Proprietary ? Proprietary ? ? Un­known ? 2001 (2001)
Signal Linux, macOS, Windows, Android, iPhone GPLv3 clients and AGPLv3 server Free RingRTC (WebRTC over Signal protocol[26]) Opus[26] ? Un­known Signal also allows users to send text messages, files, voice notes, pictures, GIFs, and video messages over a Wi-Fi or data connection to other Signal users on iOS, Android and a desktop app. The app also supports group messaging, read receipts and typing indicators, both of which can be disabled.
Android5.2.3 / 16 January 2021 (2021-01-16)[27]
iOS5.2.1 / 18 January 2021 (2021-01-18)[28]
Desktop1.39.6 / 19 January 2021 (2021-01-19)[29]
Skype Linux(with limited functionality),[30] macOS, Windows 2000-XP-Vista-7-Mobile (unsupported), BREW, Windows Phone, Android, iPhone, PSP Proprietary Free Proprietary P2P protocol [lower-alpha 1] SILK TLS 25 starting with version 3.6.0.216. 10 with 2.x Conferencing, video, file transfer, voicemail, Skype to phone, phone to Skype, additional P2P extensions (games, whiteboard, etc...); depending on platform.
Windows, UWP15.68.96.0 / 18 January 2021 (2021-01-18)[31]
Windows, desktop8.68.0.96 / 18 January 2021 (2021-01-18)[31]
macOS8.68.0.100 / 18 January 2021 (2021-01-18)[31]
Linux8.68.0.100 / 18 January 2021 (2021-01-18)[31]
Android8.68.0.97 / 18 January 2021 (2021-01-18)[32]
iOS8.68.0.97 / 18 January 2021 (2021-01-18)[33] (iPhone), [34] (iPad)
TeamSpeak Linux, Windows, macOS, FreeBSD, Android, iOS Proprietary Free Un­known CELT, Speex (both until server version 3.5.0), Opus[35] Yes 32 unlicensed, 512 with Non-Profit License (available until September 2018), up to 1024 (Gamer License), 2000 Simultaneous server conferencing with tabs, 3D sound effects, scalable permissions system, firewall friendly file transfers, in-game overlay for DirectX & OpenGL games, global public server list, plugin system 3.5.5; November 4, 2020 (2020-11-04)
TeamTalk Linux, Windows, macOS, Android, iOS, Raspbian Proprietary Free Proprietary Opus, Speex, WebM No 1000 Video, file sharing, desktop sharing, stream media files (MP3, AVI) 5.3.3; November 2018 (2018-11)
TeamViewer Linux, Windows, macOS, iOS, Android[36] Proprietary Free (personal use only) Un­known Un­known AES256 Un­known Un­known
Windows (desktop app)15.14.5 / February 1, 2021 (2021-02-01)[37]
macOS15.14.5 / February 1, 2021 (2021-02-01)[38]
Linux15.14.5 / February 1, 2021 (2021-02-01)[39]
Android15.14.35 / January 26, 2021 (2021-01-26)[40]
iOS15.14.1 / January 26, 2021 (2021-01-26)[41]
Windows (UWP app)15.100.209759[42]
BlackBerry OS12.0.0.6394 / February 1, 2017 (2017-02-01)[43]
Chrome OS15.0.14842 / November 19, 2019 (2019-11-19)[44]
Telephone macOS 10.10.2 BSD Free SIP, STUN, ICE Un­known No Un­known Address Book integration 1.1.4; March 6, 2012 (2012-03-06)
Toktumi Unlimited, Line2 Pro Windows XP-Vista-7, macOS, iOS, Android Proprietary Free Proprietary with SIP core Un­known Un­known 20 Conferencing, voicemail, caller ID, call-waiting, address book integration; auto-attendant, call-forwarding Windows; August 2010 (2010-08); macOS; October 2010 (2010-10)
Tox Linux, macOS, Windows, Android, FreeBSD GPL Free Tox, VP8 Opus, NaCl Un­known Voice, video, instant messaging, file transfers Un­known
Tru App Windows 2000-XP-Vista-7, macOS, Linux
iOS, Android, Symbian, BlackBerry OS,
Proprietary Free SIP, XMPP Un­known Un­known Un­known Chat, file transfer, voicemail, inbound numbers, integration with GTalk, Microsoft Live, Skype
Tuenti Android, iPhone, Windows Phone Proprietary Free WebRTC, SIP, XMPP iLBC, Opus Yes Un­known Voice, video, Instant messaging, group chat, photo and video sharing, SMS and MMS, native and social network contacts integration, incoming call/IM push notifications.
Twinkle Linux GPL Free SIP G.711 A-law μ-law, G.726, GSM, iLBC, Speex narrow wide ultrawide SRTP, ZRTP 3 Conferencing, chat, file transfer, Firefox integration, call redirection, voicemail, support of VoIP-to-Phone services 1.10.2 (February 14, 2019 (2019-02-14)) [±]
Ventrilo macOS, Windows, iOS, Android Proprietary Free Un­known Un­known No 8 Conferencing, chat, text-to-speech 3.0.8
Viber Linux,[lower-alpha 2] macOS,[lower-alpha 2] Windows,[lower-alpha 2] Android, Bada, BlackBerry OS, iOS, Series 40, Symbian, Windows Phone Proprietary ? Un­known Un­known Yes[47] Un­known Varies by platform: Text, picture and video messaging on all, voice calling only on iPhone, Android and Microsoft's Windows Phone
Android12.4.0.29 / February 20, 2020 (2020-02-20)[48][49]
iOS11.8 / November 3, 2019 (2019-11-03)[50]
Windows Desktop12.8.0 / April 19, 2020 (2020-04-19)[51][52]
Windows UWP6.6.1 / [unknown]
Linux12.0.0.7 / November 18, 2019 (2019-11-18)[53]
Vonage Linux, macOS, Windows, Android, iOS Proprietary not free SIP, STUN, ICE, TURN Audio: Opus, G.711

Video: VP8

SRTP 50 VoIP, video, instant messaging, presence (SIP SIMPLE), PSTN (inbound and outbound), call waiting, call hold, call forwarding, voicemail, message-waiting indication, 3-way conferencing, contacts integration, receptionist console, video, group chat, content sharing, SMS over IP services, native and social network contacts integration, incoming call/IM push notifications, fax, file sharing, screen sharing (desktop only), number programmability.
Wire Linux, Windows, macOS, iOS, Android, Web GPLv3 not free ? Audio: Opus

Video: VP8

DTLS, SRTP[54] 10[55] End-to-end encryption by default for everything, instant messaging, video call, video group call, file sharing, GIF sharing, push to talk, edit message, delete message (on both side), timed messages, doodling, identity verification, screen sharing (desktop only) ?
X-Lite macOS, Windows Proprietary Free SIP, STUN, ICE, TURN H.263, H.263+, G.711, iLBC, Speex No 3 VoIP over WiFi, 3G, 4G, video, instant messaging, presence (SIP SIMPLE), call waiting, call hold, call forwarding, voice mail, message waiting indication, 3 way conferencing, contacts integration, background noise reduction (BNR), automatic gain control (AGC) 5.3.3 July 10, 2018 (2018-07-10)
Yahoo! Messenger Classic Mac OS (8, 9), macOS, Windows, (Linux, FreeBSD version VoIP incapable) Proprietary Free SIP (using TLS) and RTP (media) Un­known Un­known Un­known Video, file transfer, PC to phone, phone to PC Windows: 11.5.0.228; May 31, 2012 (2012-05-31)
Mac: 3.0.1; July 20, 2011 (2011-07-20)
Linux: 1.0.6; September 2003 (2003-09)
SunOS 5.7: 0.99.17-1; September 2003 (2003-09)
Solaris 8: 1.0.4; September 2003 (2003-09)
FreeBSD 4-5: 1.0.4; September 2003 (2003-09)
iOS: 2.2.6; July 12, 2012 (2012-07-12)
Yate Client Linux, macOS, Windows GPL Free SIP, IAX, XMPP, H.323 G.711a, G.711u, GSM 06.10, iLBC, Speex, G.723, G.726, G.728, G.729 SRTP, maybe ZRTP? Un­known 6.0.0; September 2017 (2017-09)
Zfone Linux, macOS, Windows Proprietary (with viewable source) Includes time bomb provision SIP, RTP Un­known SRTP, ZRTP Un­known Beta 2008-09-04 (Linux 0.9.224), (macOS 0.9.246), (Windows 0.9.206)
  1. It is possible to connect by SIP to the Skype network via additional "Skype Connect" PBX software and alternative (SIP) client software/hardware. Neither the Skype software nor the Skype network supports SIP directly[1]
  2. Viber must be first installed on a mobile phone to function on a desktop operating system[45][46]

Discontinued softphone service

Mobile phones

For mobile VoIP clients:

Program Operating systems License Open source Protocols Codecs Encryption Other abilities Latest release
Acrobits Softphone Android v2.2+, iOS v7.0+ Proprietary No SIP G.711, G.722, iLBC, GSM, G.729 TLS, SRTP, ZRTP VOIP over Wi-Fi or 3G iOS only: push notifications, video, number rewriting, address book matching, sms for betamax providers and pennytel Acrobits Softphone: 3.20 (Android), 5.2 (iOS)
CounterPath Corporation Bria Android v4.4+, iOS v10+ Proprietary No SIP G.722 wideband, G.711a, G.711u, iLBC, G.729a, SILK, GSM, VP8, H.264, Opus TLS, SRTP, ZRTP Voice and video calling, SIP and XMPP messaging support, group chat, file, image and document sharing, contact integration, incoming call/IM push notifications. 5.3.4 July 23, 2018 (2018-07-23)
CSipSimple Android GPL Yes SIP Opus, AMR-WB, G.722, iSAC, iLBC, Speex, Silk, Codec2, G.726, G711 (PCMA & PCMU), AMR, GSM SRTP, SIP over TLS 1.0 and ZRTP ? 1.02.02
Google Duo iOS, Android Proprietary, freeware No WebRTC ? ? One-to-one voice and video calling.
Android114.0 / November 26, 2020 (2020-11-26)
iOS114.0 / November 20, 2020 (2020-11-20)
iCall Mobile iOS v4.3+ Proprietary, freeware No SIP AIM ICQ XMPP, Facebook, Yahoo! Messenger, Windows Live Speex, CELT, WebM TLS, ZRTP VoIP over Wi-Fi or 3G, SMS, voicemail 2.0.1; April 2012 (2012-04)
Jajah Mobile Web Symbian, Windows Mobile (version unknown) Proprietary No ? ? ? web based service, Call back, no download[56] ?
JusTex by Juphoon Android, iOS v5.1+ Proprietary No SIP PCMA, PCMU, G.722, iLBC, iSAC, Opus, H.264, VP8, H.263 TLS, TCP, UDP, SRTP JusTex Softphone over Wi-Fi or 3G, HD voice and video call, Multiparty call, conference. 3.0.1 (iOS); July 13, 2014 (2014-07-13); 3.0 (Android); July 9, 2014 (2014-07-09)
Line Android, iOS Proprietary No ? ? ? ?
Line2 Android, iOS Proprietary, freeware No Proprietary with SIP core ? ? Tri-mode calling (cellular, 3G/4G data, Wi-Fi), SMS over IP, visual voicemail, 20-person conference calls, auto-attendant, call-forwarding 1.0.4 Android, 3.2.1 iOS
Media5-fone iOS, Android Proprietary No SIP PCMA, PCMU, G.722*, iLBC, iSAC*, G.729* TLS*, SRTP* Wi-Fi and 3G/4G data, second call*, conference calls*, HD Voice, Bluetooth* (* Additional fees) ?
Signal by the Signal Foundation iOS, Android GPLv3 Yes WebRTC[57] Opus[57] TLS, Signal Protocol[57] End-to-end encryption by default for everything. CallKit and location privacy,[58] one-to-one and group messaging, video calling,[58] image/video sharing, timed messages, identity verification, screenshot blocking. Android only: SMS/MMS messaging, doodling,[59] GIF sharing.[60]
Android5.2.3 / 16 January 2021 (2021-01-16)[61]
iOS5.2.1 / 18 January 2021 (2021-01-18)[62]
Desktop1.39.6 / 19 January 2021 (2021-01-19)[63]
Sipdroid Android GPL Yes SIP ? ? Uses Wi-Fi, 3G or EDGE 2.7
Tango by TangoME Inc. iOS, Android, Microsoft Windows, macOS, Windows Phone Proprietary, freeware ? ? ? ? VoIP, Wi-Fi out & in, SMS over IP, call-through & call-back, instant messaging, videoconferencing ?
Truphone Nokia-Symbian, iOS, Android, BlackBerry Proprietary, freeware No SIP ? ? VoIP, Wi-Fi out & in, SMS over IP, call-through & call-back, connection management, provisioning Symbian 4.0, iOS 1.11.1
Vopium Symbian, Java ME, Android, BlackBerry RIM, iOS, Windows Mobile 2003 SE and higher Proprietary, freeware No SIP, MSN, Skype, Yahoo, AOL, ICQ, Google Talk, Facebook & Twitter GSM ? Wi-Fi VoIP, GSM call-through, SMS over IP, least cost routing, synchronising-backup mobile contacts and calendar 2.0
WhatsApp

Android, BlackBerry, iOS, Symbian, Windows Phone

Proprietary, freeware No ? ? ECDH, SRTP[64] VoIP and instant messaging over Wi-Fi or a data connection.
iOS2.21.11 / January 11, 2021 (2021-01-11)[65]
Android2.21.1.13 / January 22, 2021 (2021-01-22)[66]
Windows2.2100.7 / January 16, 2021 (2021-01-16)[67]
Windows Mobile 6 Windows Mobile 6 Professional/Standard Proprietary No SIP to publicly and non-publicly routable servers ? ? Wi-Fi Mobile VoIP 6.1
X-PRO for Pocket PC Windows Mobile 2003 (earlier versions support Windows PocketPC 2002) Proprietary, discontinued in April 2007[68] No SIP ? ? Supported devices: AudioVox Maestro, Compaq/HP iPAQ: 365x, 37xx, 385x, 395x, hx4700, Dell Axim X51, X51v, Toshiba e550, e570. iPAQ 545x and Toshiba e7xx are not supported.[69] 2.2
Yuilop Android, iOS

, Windows Phone, BlackBerry OS

Proprietary, freeware No XMPP, RTP iLBC TLS VoIP over 3G-4G-LTE and Wi-fi, SMS, group chat, photo sharing, Location sharing, virtual phone numbers iOS 2.4 (November 26, 2014 (2014-11-26)[70]) [±]

Android 2.0.2 (February 12, 2014 (2014-02-12)) [±]
Windows Phone 7.x 1.0.1.7 (September 12, 2013 (2013-09-12)) [±]
Windows Phone 8.x 1.0.0.4 (September 18, 2013 (2013-09-18)) [±]
BlackBerry OS 1.0.1 (May 31, 2013 (2013-05-31)) [±]
Kindle Fire 2.0 (December 19, 2013 (2013-12-19)[71]) [±]

Linkus Android V4.4+, iOS v10.0+ Proprietary, freeware No SIP iLBC TLS, SRTP HD VoIP Call, Instant Messaging, Conferencing, SRTP Secure Media, Presence information iOS 2.7.9

Android 2.7.12

Frameworks and libraries

Program Operating systems License Protocols, based on, compatible with Encryption Other abilities Key and target markets Latest release
Tapioca Linux GPL Telepathy (software) No 0.3.9; June 12, 2006 (2006-06-12)
Telepathy, Farstream Linux, macOS, Windows LGPL SIP, XMPP (Jingle), ICE (STUN/TURN), UPnP No Multi-user A/V conferencing, IM, collaborative applications Mobile devices (Maemo, Meego), Linux desktop or embedded spec 0.27.2; September 24, 2013 (2013-09-24)
OPAL Windows, Linux (including embedded variants), macOS MPL SIP, H.323, IAX2, CAPI, VXML Un­known Multi-user A/V conferencing, IM, IVR Softphones, softswitches, telephony application servers 3.14.3; October 10, 2014 (2014-10-10)
GNU oSIP Linux, Windows, macOS, Android, iPhone, BlackBerry LGPL SIP, SDP Un­known Multi-user A/V conferencing, IM, IVR Softphones, embedded and mobile devices, telephony application servers 4.1.0; December 18, 2013 (2013-12-18)

Server software

Program Operating systems License Protocols, based on, compatible with Encryption Other abilities Key and target markets Latest release
3CX Phone System Windows, Linux Proprietary SIP TLS, SRTP Voice and video IP telephony and conferencing, voice mail and instant messaging < 50,000 users 16.2; July 5, 2019 (2019-07-05)
AS5300 Linux, Windows Server 2003 Proprietary SIP, UNIStim, MLPP SSL, TLS,

SRTP, SDESC

Voice and Video IP telephony, Voice and Video conferencing, voice mail and instant messaging 1,000 - 25,000 users 1.0; January 2008 (2008-01)
AskoziaPBX no additional OS required (Linux based) GPL, Open core SIP, H.323, IAX, SCCP No ISDN, analog, Voicemail, Conferencing, MOH, ACD, IVR, Call forwarding, Call recording SMEs up to 50 users 2.2.2; December 2012 (2012-12)
Asterisk PBX Linux, BSD, macOS, Solaris GPL, optional: Proprietary[72] SIP, H.323, IAX, MGCP, VOFR, XMPP, Google Talk, TDM TLS, SRTP VoIP Gateway, voicemail, basic accounting (can be expanded by interface with ODBC-compliant database), billing, conferencing, hot-desking, IVR trees with conditional logic, call queuing, automated call distribution Enthusiasts, developers, enterprise users (capacity dependent on server design, scalable across multiple servers) 18.2.0 (21 January 2021 (2021-01-21)[73])

17.9.1 (22 December 2020 (2020-12-22)[74])
16.16.0 (21 January 2021 (2021-01-21)[75])
13.38.1 (22 December 2020 (2020-12-22)[76])

Brekeke SIP Server Linux, Windows Proprietary SIP TLS, SRTP SIP Registrar, SIP Proxy SIP Service Providers, VoIP service providers, Healthcare, Security 3.9.1.3; December 21, 2018 (2018-12-21)
Brekeke PBX Linux, Windows Proprietary SIP TLS, SRTP Voice and Video IP telephony, Voice and Video conferencing, and voice mail Hosted service providers, Mid-large enterprise 3.9.1.4; December 27, 2018 (2018-12-27)
CallMax Softswitch Linux Proprietary SIP, H.323 SSL, TLS, HTTPS Integrated billing, IP PBX Platform, Calling card platform, Callshop module, Customer Web Portal, Retail SMS Platform. SIP Service Providers, Residential & Business VoIP providers, Corporate Clients, Other Class 5 softswitch users 3.6; October 2015 (2015-10)
CommuniGate Pro Linux, BSD, macOS, Windows, Solaris, HPUX, AIX Proprietary SIP, XIMSS Protocol, XMPP, WebRTC SSL, TLS, SRTP SIP Registrar/Proxy, Authentication, Diameter, RADIUS, ENUM, many others Carriers, enterprises, MNOs, ISPs, SaaS providers 6.1.11; June 2016 (2016-06)
Dial-Gate Softswitch PBX Linux, Windows Proprietary SIP TLS, SRTP Billing server, real-time account and line monitoring, web-based user interface Softswitch users, service providers 4.3; June 2014 (2014-06)
Dial-Office IP-PBX Linux, Windows Proprietary SIP TLS, SRTP Unified Communications, Conferencing, remote worker support and voice mail Small businesses, Mid-large enterprises 4.1; December 2013 (2013-12)
Elastix Linux GPL SIP, IAX, H323, XMPP TLS, SRTP Unified communication server that also supports chat, mail and fax. Capacity dependent on server design, scalable across multiple servers 2.5.0 (stable), 3.0.0 (stable), 4.0.0 (stable); February 10, 2016 (2016-02-10)
FreeSWITCH Linux, BSD, macOS, Solaris, Windows Mozilla Public License SIP, NAT-PMP, STUN, SIMPLE, XMPP, Google Talk (Jingle), IAX, H.323, MRCP, RSS, Skype TLS, SRTP, ZRTP Recording, Voicemail, Conferencing, RADIUS, ENUM, IM Proxy, Streaming, Media gateway, Soft-PBX, IVR (modular) Large soft-switch users, home PBX users, softphone users 1.10.4 (August 5, 2020 (2020-08-05)[77]) [±]
FreePBX Linux, BSD, Solaris GPL SIP, IAX, H323, XMPP TLS, SRTP Complete PABX Service, based on Asterisk and PHP 5.6; provides a full replacement for a legacy non-VoIP phone system; under current and active development Scales from Raspberry PI (3 users) to multiple parallel clusters (10K+ simultaneous calls) 14.0; August 2017 (2017-08)
GNU Gatekeeper Linux, FreeBSD, macOS, Windows XP-2000-Vista-7 GPL H.323 H.235 H.460.18 firewall traversal, routing, accounting video conferencing, VoIP carriers large and small 3.7; August 15, 2014 (2014-08-15)
HERO Hosted PBX Linux, Windows Proprietary SIP TLS, SRTP Unified Communications, billing server, cloud-based management and web interface Mid-large enterprises, VoIP carriers and service providers, telecom operators 4.3; December 2013 (2013-12)
Kerio Operator Linux, VM Proprietary SIP SSL, TLS, SRTP integrated firewall, Auto attendant, Call queues, Conference calling, Call forwarding, pickup, parking, recording, Click to Call, Video calling, Fax support, Paging, Salesforce.com and CRM integration, Voicemail to email, complementary desktop Softphone app SME 2.5.2; November 15, 2016 (2016-11-15)
MediaCore SBC Linux Proprietary H.323, SIP, SMPP, HTTP SSL, TLS, HTTPS Dynamic routing mechanism including LCR, Jurisdictional routing support, origin based routing, integrated billing, SIP-H.323 protocol converter, Transcoding - codec converter module, Guardian - revenue assurance module, SBC functionality, full and media proxy, Wholesale messaging and SMS hubbing Transit VoIP services providers, VoIP wholesale carriers, VoIP termination providers, Wholesale messaging providers 4.8; February 2021 (2021-02)
Murmur Linux, BSD, macOS, Windows BSD, GPL CELT, Speex, Opus TLS Chat with (limited) embedded HTML, ACLs for user management, Customizable In-Game Overlay, Directional Audio, Plugin Support, Nested Channels Individuals to Small and medium enterprise (25-5000 users) 1.2.17; September 24, 2016 (2016-09-24)
Mysipswitch Linux BSD SIP, Ajax SSL SIP proxy server which allows the use of multiple SIP accounts with a single SIP login Individuals August 2007 (2007-08)
Objectworld UC Server Windows XP-2003-2008 Proprietary SIP No IP PBX, personal assistants, IVR, automated phone provisioning, fax server, unified messaging, Outlook, Exchange and Lotus Domino-Notes integration, conferencing, outbound dialing Small and medium enterprise (25-2000 users) 4.4.2; May 2009 (2009-05)
Kamailio, OpenSIPS (formerly named OpenSER) Linux, BSD, Solaris GPL SIP, XMPP TLS, SRTP SIP registrar-proxy, authentication, Diameter, RADIUS, ENUM, least-cost-routing, many others SIP Service Providers 5.2.8; October 2020 (2020-10)
Pbxnsip Linux, BSD, macOS, Windows Proprietary SIP SRTP IP PBX, presence indication, IVR, automated phone provisioning, fax server, unified messaging, Outlook, Exchange integration, conferencing, outbound dialing Small and medium enterprise (25-256 users) 3.3.1.3177; April 2009 (2009-04)
SIP Express Router (SER) Linux, BSD, Solaris GPL SIP No SIP Registrar/Proxy, Authentication, Diameter, RADIUS, ENUM, many others SIP Service Providers 2.0.0 Ottendorf
sipXecs IP PBX Linux AGPL Native SIP call control, XMPP TLS, SRTP Full redundancy (HA), instant messaging, voicemail, user portal, admin GUI, plug & play management including phones and gateways, fully featured Enterprises between 10 and 10,000 users, multi-site 14.04.2; July 2014 (2014-07)
vzRoom Windows Proprietary SIP SSL, TLS, AES Instant messaging-chat, VoIP, video, sharing (desktop, video, file), whiteboard, scheduler, recording Individual to small and medium enterprise (2-1,000 users) 0.8.8.735; November 2010 (2010-11)
Yate BSD, Linux, macOS, Windows GPL SIP, IAX, H.323, ISDN, XMPP (Jabber), Jingle (Google Talk), MGCP, SS7 over IP, Cisco SLT (Signalling Link Transport) (SS7 MTP2 backhaul over IP), SCTP, SCCP, TCAP, MAP CAMEL SSL, TLS, SRTP Voice, video, file transfer, data, H323 to SIP signalling proxy, instant messaging, IVR, PC2Phone and Phone2PC gateway, SCCP — GTT routing between networks, Secure Unified Communications, SIP registrar-proxy, SIP SBC (session border controller), USSD, voicemail, VoIP, VoIP to PSTN gateway, conference server (max 200 voice channels per conference), call centre server, prepaid and postpaid cards Deployed on home servers and large networks with millions of users 5.5; May 2015 (2015-05)

Secure VoIP software

VoIP software with client-to-client encryption

The following table is an overview of those VoIP clients which (can) provide end-to-end encryption.

Client name Development status Open source client End-to-end authentication[lower-alpha 1] Encryption protocols Forward secrecy Multiple encryption Encrypted group calling Proxy, Tor
ZRTP ECDH DTLS SRTP
FaceTime Active No[78] No[78] ? ? ? ? Yes[78] ? No No
Google Duo Active No No ? ? ? ? ? ? No No
Jitsi[lower-alpha 2] Active Yes Yes[78] Yes No Yes Yes Yes[78] Yes Yes ?
Line[79][80] Active No ? ? ? ? ? ? ? No[79] No
Linphone[lower-alpha 2] Active Yes Yes Yes ? Yes Yes Yes Yes ? No
PGPfone Abandonware Viewable source[81] Yes ? ? ? ? ? ? ? ?
Signal Active Yes Yes[78] No Yes No Yes Yes[78] Yes No Depends[82]
Silent Phone Active Viewable source[83] Yes[78] Yes ? ? Yes Yes[78] Yes Yes No
Skype
(opt-in per conversation,
one pair of devices per conversation)[84]
Active No Yes[85] No No No Yes[86] ? ? No No
Telegram Active Yes Yes[87] No No No No Yes ? No No
Threema Active Partially[lower-alpha 3][88] Yes[89] No Yes[89] Yes[89] Yes[89] Partially[lower-alpha 4][89] Yes No No
Viber[47] Active No ? ? ? ? ? ? ? ? No
WhatsApp Active Partially[lower-alpha 3][90] Yes[90] No Yes[90] No Yes[90] Yes[90] Yes[90] No No
Wire Active Yes Yes[91] No ? Yes[54] Yes[54] Yes[92] Yes Yes No
Zfone Abandonware Viewable source[93] Yes Yes Optional[94] ? Yes[95] Yes Yes ? ?

VoIP software with client-to-server encryption

The following table is an overview of those VoIP clients which (normally) provide client-to-server encryption.

Client name Encryption protocols
Google Hangouts[78] SRTP[96]
Skype[78] A custom protocol
Notes
  1. End-to-end authentication protects communications from man-in-the-middle attacks by the service provider.
  2. Only if the user has registered with a compatible SIP provider. Some SIP providers do not support certain encryption protocols.
  3. Only the encryption related source code is open.
  4. Only on the network connection, not on the end-to-end layer.

See also

References

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