Browse free open source VoIP apps and projects for Android below. Use the toggles on the left to filter open source VoIP apps by OS, license, language, programming language, and project status.
Java VoIP Softphone (SIP) (replaced by jfPhone)
Baresip is a modular SIP User-Agent with audio and video support
The OZEKI VoIP Service Checker allows you to check VoIP services.
Optimized and cross platform SMPTE 2022 FEC library in C, Python, Java
Unified Communications System - PBX System
Open source streamlined SIP client built on Linphone
C++ SIP stack based on Chrome source code