Open-source voice calls

4 voice calls whose code is public under an OSI-approved license, rated for privacy with evidence. Picks first, then by score.

1. Baresip Grade B

   Portable, modular SIP client with audio and video calling, mainly used from the command line. It supports SRTP, ZRTP and many audio and video codecs.

   Open source under the BSD-3-Clause license. Source code

2. Mumble Grade C

   Open source, low-latency voice chat client and server (Murmur) for groups, with encrypted connections and self-hosted servers.

   BSD-3-Clause. Source code

3. Linphone Grade D

   Open source SIP softphone for audio and video calls and instant messaging, with end-to-end encrypted chat and apps for Android, iOS, Windows, macOS and Linux. Developed by Belledonne Communications.

   GPL-3.0. Source code

4. MicroSIP Grade F

   Lightweight portable SIP softphone for Windows, built on the PJSIP stack, for voice and video calls through any SIP provider.

   GPL-2.0; source archives are published for each release. Source code

Compare all 6 voice calls, open source or not.