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
Unified Communications Server
A simple noise gate app intended for use with VOIPs like Skype.
Matrix reference homeserver
Browse on Tor / i2p - Anon p2p Chat / FileTx, Conf / Video VoIP
Java VoIP Softphone (SIP) (replaced by jfPhone)
Java wrapper for the popular chat & VOIP service
http://www.vaakpbx.com
High performance, production quality STUN server and client library
H.323 Gatekeeper for VoIP and videconferencing
Free, native Windows SIP softphone with HD audio, SRTP encryption
OpenSource Call Center and Dialer System
SMS, Fax, Voice Broadcasting and auto dialer Software
For more VoIP resources for business, take a look at the business VoIP category.