Browse free open source VoIP software and projects for Windows 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
Unified Communications Server
A simple noise gate app intended for use with VOIPs like Skype.
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
H.323 Gatekeeper for VoIP and videconferencing
Free, native Windows SIP softphone with HD audio, SRTP encryption
High performance, production quality STUN server and client library
An administration web interface for Mumble VoIP servers in PHP
1 on 1 Webcam Videochat Script with P2P Support
ERP, IP PBX, Accounting, CRM, Time tracking, and etc.
Skype language files for additonal languages (details below)
Baresip is a modular SIP User-Agent with audio and video support
Modern, AI-Smart, WASTE p2p for ipv4, Tor and i2p + Voice Conference.
Java VoIP/SIP PBX system (replaced by jfPBX)