Open Source SIP Client for Android

The first step in the Open Secure Telephony Network (OSTN) is a client. We can’t make a phone call without a phone. In this case there are three primary goals and a number of optional features. The primary goal is an application which speaks the SIP protocol for signalling. It must also speak the ZRTP protocol for peer to peer encryption key exchange. Finally the client must have source code freely available with a license that allows free redistribution.

As of today, the only client for Andriod that fufills this qualification is named CSipSimple. Also as of today, the ZRTP functionality is only available from a nightly build of the binary package. Your mobile handset will not allow you to install this package until you enable “Unknown sources” in the Applications settings of your phone. By default this option is disabled on all phones. To do this, open Settings from the application menu and select Applications. Check the “Unknown sources” box. Some handset vendors disable this process (referred to by the euphemism “sideloading”) though there are workarounds. Remember, don’t install the version from the market, since that does not support the ZRTP protocol. You must type in the URL for the nightly build in the handset’s browser and download the .apk. Once the package is installed, future updates may be installed through the CSipSimple application settings menu.

CSipSimple offers some nice features. It abstracts the dizzying array of configuration options required by any application that wishes to speak the SIP protocol with another. It also has some template configuration for external service providers, which I will get to in my next post.

CSipSimple. Do it!

Original post created at 2012-01-14 05:19:02 UTC Permalink

9 comments for “Open Source SIP Client for Android

  1. Viktor
    2012/02/24 at 11:43 am

    Thanks guys, IMHO your work on CSipSimple is extremely important, specially after the adquisition of Whispersys by Twitter.

    Which security/privacy apps can you recommend besides yours?


    • n8fr8
      2012/03/13 at 9:16 am

      Hey Viktor. In general, you can check our /apps or “Mobile Apps” pages for other apps we know and endorse.

      Android Privacy Guard and K9 mail are the other two primary apps we utilize beyond our own. Also, the F-Droid open-source repo project is a good place to get your apps if you want to move away from the Google Play/Android Market ecosystem.

      Is there a particular piece of functionality you are looking for?

  2. karel
    2012/06/11 at 3:12 pm

    There seems to be some new ZRTP development. Any opinion about it?

    • n8fr8
      2012/06/13 at 7:49 pm

      Lumicall looks to be a complete open standards based Android client, which should work with our own OSTel/CSipSimple application.

      This is what we want – more choice of apps, but all able to interoperate.

      We will add it to our testing matrix. See this link for all the apps we are testing and supporting:

  3. Bartha Arthur
    2014/03/06 at 3:01 pm

    Also i would recommend to try mizudroid android softphone if you are having problems with csipsimple:
    It is working fine for me after i spent more than a hour bringing csipsimple to life.

  4. SimonR
    2015/02/23 at 4:36 am

    Hello, Could you tell me whether this app is compatible with Ozeki VoIP SIP SDK ( or not? Or could you recommend me a VoIP SIP stack that can be used to add further features to this Android application? Thanks in advance

  5. 兴兴
    2015/03/24 at 8:44 am

    hello ,recently, i am studying the sip vedio communications at school,so i would appreciate it very much if you send me a piece source codes of the client. It must help me more about my study.Thanks very much.

  6. 2016/05/09 at 8:55 am

    i wan to make an free call application using internet with lumi call…. i just want all features mine in this app just with lumicall call at any number …. how it will be possible ? what will be the cost ..etc ? please tell me at as possible as fast …

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