SIP H323 customized softphone, webdialer, VOIP software



The world leader in softphone production

SJ Labs is a world leader in VoIP softphone development winning numerous industry awards over the years. Founded in 1999 and based in Solon, Ohio, our VOIP platform has hundreds of man-years of development and has been deployed for over five years. Our softphone has been used and downloaded by over 2 million users.


The Ultimate Voice and Video solution for ITSP around the Globe

We have hundreds of ITSP customers around the world. Our diverse product line will meet your need regardless if you are a small, local new regional ITSP looking for a cost effective competitively featured client solution or a traditional large telecommunication company looking to enhance your branded triple threat options with customized state-of-the-art voice and video solutions integrated into your existing “look and feel” voice services platform.

Since 2002, when first in the world we introduced a PDA softphone, SJphone has supported most modern wireless PDAs or EDAs with Windows CE or Linux.

What our users are saying:

”The sound [ with SJphone ] is so good, that we need low level comfort noise, otherwise you don't know the call is still active.” Henry Sinnreich, MCI

"It is the best of all available clients for iPAQ (sip and h323) we have evaluated!!" Tom Jacobs, Alcatel

"ViewSonic has implemented the SJ Labs VOIP softclient across PDA, Webpad and Visual Client product form factors with excellent results. This has not been done before so the technical achievement with SJ_Labs exceeded our expectations and our customers," said Marc McConnaughey, Senior Vice President, ViewSonic.

SJphone Awards:

The first softphone for PDA Softphone Award


SJ Labs News

May 5, 2007. We published the latest free version SJphone 1.65 for MAC and Linux with new cool skin and improved SIP. You can download it from our preview area.

Apr 4, 2007. We published the latest free version SJphone 1.65 with new cool skin, Jabber IM and improved SIP. Try it:

download SJphone 1.65 for Windows

download 1.65 readme

Mar 20-23, 2007. We participated in VON Spring'07 in San Jose, CA.

Sept 12, 2006. SJ Labs announced that our award-winning product SJphone supports Intel(r) Universal Phone Device Interface (UPDI). Read Intel press release here.

Sept 11-14, 2006. We participated in VON Fall'06 at Convention and Exhibition Center, Boston, MA.

March 16, 2006. SJ Labs, PortaOne integrate software products for ITSPs. SJ Labs, US-based specialist in VoIP software, has reached a deal with PortaOne, specialist in internet telephony billing solutions, to integrate their flagship software products to create an on-demand 'media-over-IP' solution for internet telephony service providers (ITSPs). SJ Labs will integrate its SJphone product, a customisable on-line softphone, with the PortaSwitch (PortaBilling/PortaSIP) products from PortaOne, which enables efficient implementation of billing solutions for ITSPs. The alliance was announced at the Spring VON conference in San Jose, California. Also at VON, SJ Labs has announced new features for its SJphone, including support for Video and a Jabber-based Internet Messaging Program (IMP).


March 15, 2006. We participated in VON Spring'06 in San Jose, CA.

Softphone at VON

Feb 20, 2006. Now you can download the latest beta versions of SJphone for Windows, CE, Linux and MAC.  If you want to send us a change request or a bug report, please look at the latest beta first.

Dec 20, 2005 — Technology Marketing Corporation’s (TMC®) INTERNET TELEPHONY® magazine announced today this year’s winners of the magazine’s prestigious Product of the Year Awards. SJphone is one of the winners - for more information please visit

Softphone Award

Oct 25. We published SJphone CE v.1.60.303. New features are high-density screen support, Echo Canceller (AEC), Audio Wizard to tune Audio options, improved interoperability for a number of SIP softswitch vendors, and more. It was tested with several WLAN PDAs like Fujitsu-Siemens Pocket LOOX, Symbol MC50 etc. To get it please go to our Download page. All our customers are welcome to upgrade.

Sept 24. We published the new free SJphone Linux and SJphone MAC v.1.60.299. New features are Audio Wizard enabling the user to fine tune Audio options, improved interoperability for a number of SIP softswitch vendors, and more. To get it please go to our Download page.

July 19. We published the new free version of our award-winning softphone for MS Windows, SJphone v.1.60.289. It may be used for PC-to-PC calls, or with any ITSP like Vonage or FreeWorldDialup.

Apr 22. We published the new document "Creating your own profiles for SJphone", get it from our Download page.

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