Browse free open source VoIP software and projects below. Use the toggles on the left to filter open source VoIP software by OS, license, language, programming language, and project status.
Issabel PBX - Unified Communications
VoIP SIP and SKINNY quality analyzer and packet / audio recording tool
A simple noise gate app intended for use with VOIPs like Skype.
Unified Communications Server
Matrix reference homeserver
Java wrapper for the popular chat & VOIP service
Browse on Tor/i2p, Anon p2p Chat / FileTx, Conf / Video VoIP
Modern, AI-Smart, WASTE p2p for ipv4, Tor and i2p + Voice Conference.
Java VoIP Softphone (SIP) (replaced by jfPhone)
Positional Audio Communication for Minecraft with Mumble
http://www.vaakpbx.com
Java VoIP/SIP PBX system (replaced by jfPBX)
A suite of open-source tools and frameworks for creating SIP apps
High performance, production quality STUN server and client library
Free, native Windows SIP softphone with HD audio, SRTP encryption
For more VoIP resources for business, take a look at the business VoIP category.